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NORMEINTERNATIONALECEI IEC INTERNATIONALSTANDARD 61854Première éditionFirst edition1998-09Lignes aériennes –Exigences et essais applicables aux entretoisesOverhead lines –Requirements and tests for spacersCommission Electrotechnique InternationaleInternational Electrotechnical Commission Pour prix, voir catalogue en vigueurFor price, see current catalogue© IEC 1998 Droits de reproduction réservés Copyright - all rights reservedAucune partie de cette publication ne peut être reproduite niutilisée sous quelque forme que ce soit et par aucunprocédé, électronique ou mécanique, y compris la photo-copie et les microfilms, sans l'accord écrit de l'éditeur.No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical,including photocopying and microfilm, without permission in writing from the publisher.International Electrotechnical Commission 3, rue de Varembé Geneva, SwitzerlandTelefax: +41 22 919 0300e-mail: inmail@iec.ch IEC web site http: //www.iec.chCODE PRIX PRICE CODE X– 2 –61854 © CEI:1998SOMMAIREPages AVANT-PROPOS (6)Articles1Domaine d'application (8)2Références normatives (8)3Définitions (12)4Exigences générales (12)4.1Conception (12)4.2Matériaux (14)4.2.1Généralités (14)4.2.2Matériaux non métalliques (14)4.3Masse, dimensions et tolérances (14)4.4Protection contre la corrosion (14)4.5Aspect et finition de fabrication (14)4.6Marquage (14)4.7Consignes d'installation (14)5Assurance de la qualité (16)6Classification des essais (16)6.1Essais de type (16)6.1.1Généralités (16)6.1.2Application (16)6.2Essais sur échantillon (16)6.2.1Généralités (16)6.2.2Application (16)6.2.3Echantillonnage et critères de réception (18)6.3Essais individuels de série (18)6.3.1Généralités (18)6.3.2Application et critères de réception (18)6.4Tableau des essais à effectuer (18)7Méthodes d'essai (22)7.1Contrôle visuel (22)7.2Vérification des dimensions, des matériaux et de la masse (22)7.3Essai de protection contre la corrosion (22)7.3.1Composants revêtus par galvanisation à chaud (autres queles fils d'acier galvanisés toronnés) (22)7.3.2Produits en fer protégés contre la corrosion par des méthodes autresque la galvanisation à chaud (24)7.3.3Fils d'acier galvanisé toronnés (24)7.3.4Corrosion causée par des composants non métalliques (24)7.4Essais non destructifs (24)61854 © IEC:1998– 3 –CONTENTSPage FOREWORD (7)Clause1Scope (9)2Normative references (9)3Definitions (13)4General requirements (13)4.1Design (13)4.2Materials (15)4.2.1General (15)4.2.2Non-metallic materials (15)4.3Mass, dimensions and tolerances (15)4.4Protection against corrosion (15)4.5Manufacturing appearance and finish (15)4.6Marking (15)4.7Installation instructions (15)5Quality assurance (17)6Classification of tests (17)6.1Type tests (17)6.1.1General (17)6.1.2Application (17)6.2Sample tests (17)6.2.1General (17)6.2.2Application (17)6.2.3Sampling and acceptance criteria (19)6.3Routine tests (19)6.3.1General (19)6.3.2Application and acceptance criteria (19)6.4Table of tests to be applied (19)7Test methods (23)7.1Visual examination (23)7.2Verification of dimensions, materials and mass (23)7.3Corrosion protection test (23)7.3.1Hot dip galvanized components (other than stranded galvanizedsteel wires) (23)7.3.2Ferrous components protected from corrosion by methods other thanhot dip galvanizing (25)7.3.3Stranded galvanized steel wires (25)7.3.4Corrosion caused by non-metallic components (25)7.4Non-destructive tests (25)– 4 –61854 © CEI:1998 Articles Pages7.5Essais mécaniques (26)7.5.1Essais de glissement des pinces (26)7.5.1.1Essai de glissement longitudinal (26)7.5.1.2Essai de glissement en torsion (28)7.5.2Essai de boulon fusible (28)7.5.3Essai de serrage des boulons de pince (30)7.5.4Essais de courant de court-circuit simulé et essais de compressionet de traction (30)7.5.4.1Essai de courant de court-circuit simulé (30)7.5.4.2Essai de compression et de traction (32)7.5.5Caractérisation des propriétés élastiques et d'amortissement (32)7.5.6Essais de flexibilité (38)7.5.7Essais de fatigue (38)7.5.7.1Généralités (38)7.5.7.2Oscillation de sous-portée (40)7.5.7.3Vibrations éoliennes (40)7.6Essais de caractérisation des élastomères (42)7.6.1Généralités (42)7.6.2Essais (42)7.6.3Essai de résistance à l'ozone (46)7.7Essais électriques (46)7.7.1Essais d'effet couronne et de tension de perturbations radioélectriques..467.7.2Essai de résistance électrique (46)7.8Vérification du comportement vibratoire du système faisceau/entretoise (48)Annexe A (normative) Informations techniques minimales à convenirentre acheteur et fournisseur (64)Annexe B (informative) Forces de compression dans l'essai de courantde court-circuit simulé (66)Annexe C (informative) Caractérisation des propriétés élastiques et d'amortissementMéthode de détermination de la rigidité et de l'amortissement (70)Annexe D (informative) Contrôle du comportement vibratoire du systèmefaisceau/entretoise (74)Bibliographie (80)Figures (50)Tableau 1 – Essais sur les entretoises (20)Tableau 2 – Essais sur les élastomères (44)61854 © IEC:1998– 5 –Clause Page7.5Mechanical tests (27)7.5.1Clamp slip tests (27)7.5.1.1Longitudinal slip test (27)7.5.1.2Torsional slip test (29)7.5.2Breakaway bolt test (29)7.5.3Clamp bolt tightening test (31)7.5.4Simulated short-circuit current test and compression and tension tests (31)7.5.4.1Simulated short-circuit current test (31)7.5.4.2Compression and tension test (33)7.5.5Characterisation of the elastic and damping properties (33)7.5.6Flexibility tests (39)7.5.7Fatigue tests (39)7.5.7.1General (39)7.5.7.2Subspan oscillation (41)7.5.7.3Aeolian vibration (41)7.6Tests to characterise elastomers (43)7.6.1General (43)7.6.2Tests (43)7.6.3Ozone resistance test (47)7.7Electrical tests (47)7.7.1Corona and radio interference voltage (RIV) tests (47)7.7.2Electrical resistance test (47)7.8Verification of vibration behaviour of the bundle-spacer system (49)Annex A (normative) Minimum technical details to be agreed betweenpurchaser and supplier (65)Annex B (informative) Compressive forces in the simulated short-circuit current test (67)Annex C (informative) Characterisation of the elastic and damping propertiesStiffness-Damping Method (71)Annex D (informative) Verification of vibration behaviour of the bundle/spacer system (75)Bibliography (81)Figures (51)Table 1 – Tests on spacers (21)Table 2 – Tests on elastomers (45)– 6 –61854 © CEI:1998 COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE––––––––––LIGNES AÉRIENNES –EXIGENCES ET ESSAIS APPLICABLES AUX ENTRETOISESAVANT-PROPOS1)La CEI (Commission Electrotechnique Internationale) est une organisation mondiale de normalisation composéede l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de l'électricité et de l'électronique. A cet effet, la CEI, entre autres activités, publie des Normes internationales.Leur élaboration est confiée à des comités d'études, aux travaux desquels tout Comité national intéressé par le sujet traité peut participer. Les organisations internationales, gouvernementales et non gouvernementales, en liaison avec la CEI, participent également aux travaux. La CEI collabore étroitement avec l'Organisation Internationale de Normalisation (ISO), selon des conditions fixées par accord entre les deux organisations.2)Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesuredu possible un accord international sur les sujets étudiés, étant donné que les Comités nationaux intéressés sont représentés dans chaque comité d’études.3)Les documents produits se présentent sous la forme de recommandations internationales. Ils sont publiéscomme normes, rapports techniques ou guides et agréés comme tels par les Comités nationaux.4)Dans le but d'encourager l'unification internationale, les Comités nationaux de la CEI s'engagent à appliquer defaçon transparente, dans toute la mesure possible, les Normes internationales de la CEI dans leurs normes nationales et régionales. Toute divergence entre la norme de la CEI et la norme nationale ou régionale correspondante doit être indiquée en termes clairs dans cette dernière.5)La CEI n’a fixé aucune procédure concernant le marquage comme indication d’approbation et sa responsabilitén’est pas engagée quand un matériel est déclaré conforme à l’une de ses normes.6) L’attention est attirée sur le fait que certains des éléments de la présente Norme internationale peuvent fairel’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.La Norme internationale CEI 61854 a été établie par le comité d'études 11 de la CEI: Lignes aériennes.Le texte de cette norme est issu des documents suivants:FDIS Rapport de vote11/141/FDIS11/143/RVDLe rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant abouti à l'approbation de cette norme.L’annexe A fait partie intégrante de cette norme.Les annexes B, C et D sont données uniquement à titre d’information.61854 © IEC:1998– 7 –INTERNATIONAL ELECTROTECHNICAL COMMISSION––––––––––OVERHEAD LINES –REQUIREMENTS AND TESTS FOR SPACERSFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprisingall national electrotechnical committees (IEC National Committees). The object of the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC publishes International Standards. Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.2)The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, aninternational consensus of opinion on the relevant subjects since each technical committee has representation from all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in the formof standards, technical reports or guides and they are accepted by the National Committees in that sense.4)In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Any divergence between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter.5)The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subjectof patent rights. The IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61854 has been prepared by IEC technical committee 11: Overhead lines.The text of this standard is based on the following documents:FDIS Report on voting11/141/FDIS11/143/RVDFull information on the voting for the approval of this standard can be found in the report on voting indicated in the above table.Annex A forms an integral part of this standard.Annexes B, C and D are for information only.– 8 –61854 © CEI:1998LIGNES AÉRIENNES –EXIGENCES ET ESSAIS APPLICABLES AUX ENTRETOISES1 Domaine d'applicationLa présente Norme internationale s'applique aux entretoises destinées aux faisceaux de conducteurs de lignes aériennes. Elle recouvre les entretoises rigides, les entretoises flexibles et les entretoises amortissantes.Elle ne s'applique pas aux espaceurs, aux écarteurs à anneaux et aux entretoises de mise à la terre.NOTE – La présente norme est applicable aux pratiques de conception de lignes et aux entretoises les plus couramment utilisées au moment de sa rédaction. Il peut exister d'autres entretoises auxquelles les essais spécifiques décrits dans la présente norme ne s'appliquent pas.Dans de nombreux cas, les procédures d'essai et les valeurs d'essai sont convenues entre l'acheteur et le fournisseur et sont énoncées dans le contrat d'approvisionnement. L'acheteur est le mieux à même d'évaluer les conditions de service prévues, qu'il convient d'utiliser comme base à la définition de la sévérité des essais.La liste des informations techniques minimales à convenir entre acheteur et fournisseur est fournie en annexe A.2 Références normativesLes documents normatifs suivants contiennent des dispositions qui, par suite de la référence qui y est faite, constituent des dispositions valables pour la présente Norme internationale. Au moment de la publication, les éditions indiquées étaient en vigueur. Tout document normatif est sujet à révision et les parties prenantes aux accords fondés sur la présente Norme internationale sont invitées à rechercher la possibilité d'appliquer les éditions les plus récentes des documents normatifs indiqués ci-après. Les membres de la CEI et de l'ISO possèdent le registre des Normes internationales en vigueur.CEI 60050(466):1990, Vocabulaire Electrotechnique International (VEI) – Chapitre 466: Lignes aériennesCEI 61284:1997, Lignes aériennes – Exigences et essais pour le matériel d'équipementCEI 60888:1987, Fils en acier zingué pour conducteurs câblésISO 34-1:1994, Caoutchouc vulcanisé ou thermoplastique – Détermination de la résistance au déchirement – Partie 1: Eprouvettes pantalon, angulaire et croissantISO 34-2:1996, Caoutchouc vulcanisé ou thermoplastique – Détermination de la résistance au déchirement – Partie 2: Petites éprouvettes (éprouvettes de Delft)ISO 37:1994, Caoutchouc vulcanisé ou thermoplastique – Détermination des caractéristiques de contrainte-déformation en traction61854 © IEC:1998– 9 –OVERHEAD LINES –REQUIREMENTS AND TESTS FOR SPACERS1 ScopeThis International Standard applies to spacers for conductor bundles of overhead lines. It covers rigid spacers, flexible spacers and spacer dampers.It does not apply to interphase spacers, hoop spacers and bonding spacers.NOTE – This standard is written to cover the line design practices and spacers most commonly used at the time of writing. There may be other spacers available for which the specific tests reported in this standard may not be applicable.In many cases, test procedures and test values are left to agreement between purchaser and supplier and are stated in the procurement contract. The purchaser is best able to evaluate the intended service conditions, which should be the basis for establishing the test severity.In annex A, the minimum technical details to be agreed between purchaser and supplier are listed.2 Normative referencesThe following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication of this standard, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.IEC 60050(466):1990, International Electrotechnical vocabulary (IEV) – Chapter 466: Overhead linesIEC 61284:1997, Overhead lines – Requirements and tests for fittingsIEC 60888:1987, Zinc-coated steel wires for stranded conductorsISO 34-1:1994, Rubber, vulcanized or thermoplastic – Determination of tear strength – Part 1: Trouser, angle and crescent test piecesISO 34-2:1996, Rubber, vulcanized or thermoplastic – Determination of tear strength – Part 2: Small (Delft) test piecesISO 37:1994, Rubber, vulcanized or thermoplastic – Determination of tensile stress-strain properties– 10 –61854 © CEI:1998 ISO 188:1982, Caoutchouc vulcanisé – Essais de résistance au vieillissement accéléré ou à la chaleurISO 812:1991, Caoutchouc vulcanisé – Détermination de la fragilité à basse températureISO 815:1991, Caoutchouc vulcanisé ou thermoplastique – Détermination de la déformation rémanente après compression aux températures ambiantes, élevées ou bassesISO 868:1985, Plastiques et ébonite – Détermination de la dureté par pénétration au moyen d'un duromètre (dureté Shore)ISO 1183:1987, Plastiques – Méthodes pour déterminer la masse volumique et la densitérelative des plastiques non alvéolairesISO 1431-1:1989, Caoutchouc vulcanisé ou thermoplastique – Résistance au craquelage par l'ozone – Partie 1: Essai sous allongement statiqueISO 1461,— Revêtements de galvanisation à chaud sur produits finis ferreux – Spécifications1) ISO 1817:1985, Caoutchouc vulcanisé – Détermination de l'action des liquidesISO 2781:1988, Caoutchouc vulcanisé – Détermination de la masse volumiqueISO 2859-1:1989, Règles d'échantillonnage pour les contrôles par attributs – Partie 1: Plans d'échantillonnage pour les contrôles lot par lot, indexés d'après le niveau de qualité acceptable (NQA)ISO 2859-2:1985, Règles d'échantillonnage pour les contrôles par attributs – Partie 2: Plans d'échantillonnage pour les contrôles de lots isolés, indexés d'après la qualité limite (QL)ISO 2921:1982, Caoutchouc vulcanisé – Détermination des caractéristiques à basse température – Méthode température-retrait (essai TR)ISO 3417:1991, Caoutchouc – Détermination des caractéristiques de vulcanisation à l'aide du rhéomètre à disque oscillantISO 3951:1989, Règles et tables d'échantillonnage pour les contrôles par mesures des pourcentages de non conformesISO 4649:1985, Caoutchouc – Détermination de la résistance à l'abrasion à l'aide d'un dispositif à tambour tournantISO 4662:1986, Caoutchouc – Détermination de la résilience de rebondissement des vulcanisats––––––––––1) A publierThis is a preview - click here to buy the full publication61854 © IEC:1998– 11 –ISO 188:1982, Rubber, vulcanized – Accelerated ageing or heat-resistance testsISO 812:1991, Rubber, vulcanized – Determination of low temperature brittlenessISO 815:1991, Rubber, vulcanized or thermoplastic – Determination of compression set at ambient, elevated or low temperaturesISO 868:1985, Plastics and ebonite – Determination of indentation hardness by means of a durometer (Shore hardness)ISO 1183:1987, Plastics – Methods for determining the density and relative density of non-cellular plasticsISO 1431-1:1989, Rubber, vulcanized or thermoplastic – Resistance to ozone cracking –Part 1: static strain testISO 1461, — Hot dip galvanized coatings on fabricated ferrous products – Specifications1)ISO 1817:1985, Rubber, vulcanized – Determination of the effect of liquidsISO 2781:1988, Rubber, vulcanized – Determination of densityISO 2859-1:1989, Sampling procedures for inspection by attributes – Part 1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspectionISO 2859-2:1985, Sampling procedures for inspection by attributes – Part 2: Sampling plans indexed by limiting quality level (LQ) for isolated lot inspectionISO 2921:1982, Rubber, vulcanized – Determination of low temperature characteristics –Temperature-retraction procedure (TR test)ISO 3417:1991, Rubber – Measurement of vulcanization characteristics with the oscillating disc curemeterISO 3951:1989, Sampling procedures and charts for inspection by variables for percent nonconformingISO 4649:1985, Rubber – Determination of abrasion resistance using a rotating cylindrical drum deviceISO 4662:1986, Rubber – Determination of rebound resilience of vulcanizates–––––––––1) To be published.。
第52卷第11期表面技术2023年11月SURFACE TECHNOLOGY·23·耐久超疏水表面的研究进展徐文婷，傅平安，欧军飞*（江苏理工学院 材料工程学院，江苏 常州 213001）摘要：超疏水表面在油水分离、腐蚀防护、防水抗冰等领域具有广泛的研究和应用价值。
然而，其实际应用并未达到预期的广泛程度，主要制约因素在于表面的耐久性不足。
超疏水表面的失效主要体现在两个方面：一方面，由于表面粗糙结构在承受机械载荷时容易遭受高局部压力而受损；另一方面，由于低表面能分子在高温、光照和强氧化剂等刺激下容易发生分解失效。
为了解决上述问题，从耐久型超疏水表面的特点入手，提出了提高超疏水表面耐久性的典型策略。
这些策略包括：（1）构建弹性基底，这可以将微结构上的载荷转移至基体，减少微结构受损的可能性；（2）微结构保护，这种方法通过构筑刚性的护盾，保护了更低尺度的纳米结构免于受损；（3）胶黏+涂装，该策略是通过中间层连接，强化基体与表面微纳结构的结合力；（4）利用低表面能物质的自修复能力，这种方法可以在表面受损后通过自我修复特性恢复其超疏水性；（5）微结构的重建，可以在表面粗糙结构遭破坏后，使其恢复原貌。
最后，对耐久超疏水表面的发展提出了前瞻性的展望，提出了耐久超疏水表面绿色可持续发展的新方向。
关键词：鲁棒性；仿生表面；自修复；铠甲表面中图分类号：TG172 文献标识码：A 文章编号：1001-3660(2023)11-0023-17DOI：10.16490/ki.issn.1001-3660.2023.11.002Research Progress on Durable Superhydrophobic SurfacesXU Wen-ting, FU Ping-an, OU Jun-fei(School of Materials Engineering, Jiangsu University of Technology, Jiangsu Changzhou 213001, china)ABSTRACT: Superhydrophobic surfaces have emerged as an exciting area of research with immense potential in various fields.These surfaces, when designed correctly, can repel water to an extraordinary extent and find applications in oil-water separation, corrosion protection, waterproofing, and anti-icing. However, their practical application has been hindered by a lack of durability. The failure of superhydrophobic surfaces can be attributed to two main factors. Firstly, the rough surface structure is susceptible to damage under high local pressure when subjected to mechanical loads. The microstructure, which is the physical foundation of the superhydrophobicity, can be easily crushed or deformed under stress. Secondly, the low surface energy molecules, which are the chemical basis of the superhydrophobicity, tend to decompose and deteriorate when exposed to stimuli such as high temperature, light, and strong oxidants. As a result, the surface's superhydrophobicity diminishes over time.To address these challenges and enhance the durability of superhydrophobic surfaces, several strategies have been proposed. (1) The first strategy involves the construction of elastic substrates. By using elastic materials as substrates, the load on the microstructure can be transferred to the matrix, reducing the likelihood of damage. This approach ensures that the收稿日期：2023-09-28；修订日期：2023-11-07Received：2023-09-28；Revised：2023-11-07基金项目：江苏省高等学校自然科学研究重大项目（23KJA430006）Fund：The Natural Science Foundation of the Jiangsu Higher Education Institutions of China (23KJA430006)引文格式：徐文婷, 傅平安, 欧军飞. 耐久超疏水表面的研究进展[J]. 表面技术, 2023, 52(11): 23-39.XU Wen-ting, FU Ping-an, OU Jun-fei. Research Progress on Durable Superhydrophobic Surfaces[J]. Surface Technology, 2023, 52(11): 23-39. *通信作者（Corresponding author）·24·表面技术 2023年11月superhydrophobic surface remains intact even under mechanical stress. (2) The second strategy is microstructure protection. A protective shield can be constructed to safeguard the delicate micro/nanostructures from damage. This rigid shield acts as a barrier, shielding the micro/nanostructures from external forces or harsh conditions. Using materials with high mechanical strength and chemical stability prevents the degradation of the micro/nanostructure. (3) The third strategy is utilizing an adhesive+coating. By using an intermediate layer, the adhesion between the substrate and surface micro/nanostructures can be enhanced. This adhesive layer improves the overall durability of the superhydrophobic surface by providing additional support and stability. (4) The fourth strategy involves the use of self-healing materials. Superhydrophobic surfaces can be made from low surface energy materials with self-healing capabilities. These materials can restore their superhydrophobicity even after the surface has been damaged or compromised. This property ensures that the surface can maintain its water-repellent properties over a longer period. (5) The fifth strategy is the reconstruction of microstructures. This approach involves repairing or replacing the damaged microstructures to restore the surface's superhydrophobic properties and performance.Looking ahead, the development of durable superhydrophobic surfaces holds great promise. It offers new opportunities for green and sustainable solutions in various industries. By incorporating the aforementioned strategies, researchers and engineers can create superhydrophobic surfaces that are not only highly efficient but also long-lasting and resilient. These durability enhancement strategies pave the way for the practical implementation of superhydrophobic surfaces in real-world applications, enabling their widespread use and impact. This will contribute to the development of green and sustainable technologies for a wide range of applications.In conclusion, the development of durable superhydrophobic surfaces is crucial for advancing the fields of oil-water separation, corrosion protection, waterproofing, and anti-icing. By addressing the challenges related to surface durability through strategies such as constructing elastic substrates, microstructure protection, adhesive+coating, utilizing self-healing materials, and reconstructing microstructures, the practical application of superhydrophobic surfaces can be significantly enhanced. This will contribute to the development of green and sustainable technologies for a wide range of applications.KEY WORDS: robust; bio-inspred surface; self-healing; armoured surface随着生物进化的不断演进，自然界中许多生物逐渐进化出了具有超疏水性的表面，这些表面具有独特的微观结构和低表面能物质，使得水滴在其表面难以附着[1-5]。
第51卷第1期2020年1月中南大学学报(自然科学版)Journal of Central South University(Science and Technology)V ol.51No.1Jan.2020结霜初期超疏水表面液滴生长的规律赵伟，梁彩华，成赛凤，罗倩妮(东南大学能源与环境学院，江苏南京，210096)摘要：为了研究结霜初期液滴在超疏水表面的生长规律，建立结霜初期超疏水表面液滴生长的分层模型，揭示液滴在生长过程中各层温差的分布特点，并深入研究表面接触角、面积分数、基底温度以及空气相对湿度对液滴生长的影响规律。
研究结果表明：在结霜初期，液滴的Knudsen层以及主流连续区层这2部分的温差占基底过冷度的95%以上；随着表面接触角的增大，传质环节中的主流连续区层的温差减小，导致液滴生长减缓；面积分数S对液滴生长的影响较小，当S=0.04时，与其相关的热阻Rwe仅约占液滴-翅片层总热阻的0.2%；液滴生长速率随着基底温度的降低和空气相对湿度的升高而升高。
关键词：超疏水表面；液滴生长；接触角；面积分数中图分类号：TK124文献标志码：A文章编号：1672-7207（2020）01-0231-08Rule of droplets growth in the early stage of frost formation onsuperhydrophobic surfacesZHAO Wei,LIANG Caihua,CHENG Saifeng,LUO Qianni(School of Energy and Environment,Southeast University,Nanjing210096,China) Abstract:In order to study the droplets growth on the superhydrophobic surfaces in the early stage of frostformation,the model of droplets growth under frosting conditions was established.The proportion of the temperature difference of each layer in the droplets growth process was analyzed.The effects of contact angle, area fraction,substrate temperature and relative humidity on droplets growth were studied.The results show that in the early stage of frost formation,the temperature difference of the Knudsen layer and the continuum region layer account for more than95%of the total temperature difference.With the increase of surface contact angle,the temperature difference of continuum region layer decreases,which leads to the slow growth of droplets.The areafraction S has little effect on the droplets growth.When S=0.04,the related thermal resistance Rweonly accounts for about0.2%of the total thermal resistance of the droplet-fin layer.The rate of droplets growth increases as the substrate temperature decreases and the relative humidity of the air increases.Key words:superhydrophobic surfaces;droplets growth;contact angle;area fractionDOI:10.11817/j.issn.1672-7207.2020.01.026收稿日期：2019−03−12；修回日期：2019−05−23基金项目(Foundation item)：国家自然科学基金资助项目(51676033)；“十三五”国家重点研发计划项目(2016YFC700304) (Project(51676033)supported by the National Natural Science Foundation of China;Project(2016YFC700304)supported by the National Key R&D Programs during the13th Five-Year Plan Period)通信作者：梁彩华，博士，教授，博士生导师，从事制冷空调、建筑节能及可再生能源利用研究；E-mail：caihualiang@163.com第51卷中南大学学报(自然科学版)空气源热泵在冬季制热运行时不可避免地会出现结霜现象。
益生菌对阿尔茨海默病作用的研究进展发布时间：2021-12-14T06:08:15.523Z 来源：《中国结合医学杂志》2021年12期作者：宋鑫萍1,2，李盛钰2，金清1[导读] 阿尔茨海默病已成为威胁全球老年人生命健康的主要疾病之一，患者数量逐年攀升，其护理的经济成本高，给全球经济造成重大挑战。
近年来研究显示，益生菌在适量使用时作为有益于宿主健康的微生物，在防治阿尔茨海默病方面具有积极影响，其作用机制可能通过调节肠道菌群，影响神经免疫系统，调控神经活性物质以及代谢产物，通过肠-脑轴影响该病发生和发展。
宋鑫萍1,2，李盛钰2，金清11.延边大学农学院，吉林延吉 1330022.吉林省农业科学院农产品加工研究所，吉林长春 130033摘要：阿尔茨海默病已成为威胁全球老年人生命健康的主要疾病之一，患者数量逐年攀升，其护理的经济成本高，给全球经济造成重大挑战。
近年来研究显示，益生菌在适量使用时作为有益于宿主健康的微生物，在防治阿尔茨海默病方面具有积极影响，其作用机制可能通过调节肠道菌群，影响神经免疫系统，调控神经活性物质以及代谢产物，通过肠-脑轴影响该病发生和发展。
本文综述了近几年来国内外益生菌对阿尔茨海默病的作用进展，以及其预防和治疗阿尔茨海默病的潜在作用机制。
关键词：益生菌；阿尔茨海默病；肠道菌群；机制Recent Progress in Research on Probiotics Effect on Alzheimer’s DiseaseSONG Xinping1,2，LI Shengyu2，JI Qing1*(1.College of Agricultural, Yanbian University, Yanji 133002，China)(2.Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, Chanchun 130033, China)Abstract：Alzheimer’s disease has become one of the major diseases threatening the life and health of the global elderly. The number of patients is increasing year by year, and the economic cost of nursing is high, which poses a major challenge to the global economy. In recent years, studies have shown that probiotics, as microorganisms beneficial to the health of the host, have a positive impact on the prevention and treatment of Alzheimer’s disease. Its mechanism may be through regulating intestinal flora, affecting the nervous immune system, regulating the neuroactive substances and metabolites, and affecting the occurrence and development of the disease through thegut- brain axis. This paper reviews the progress of probiotics on Alzheimer’s disease at home and abroad in recent years, as well as its potential mechanism of prevention and treatment.Key words：probiotics; Alzheimer’s disease; gut microbiota; mechanism阿尔茨海默病（Alzheimer’s disease, AD），系中枢神经系统退行性疾病，属于老年期痴呆常见类型，临床特征主要包括：记忆力减退、认知功能障碍、行为改变、焦虑和抑郁等。
WHO Model Formulary for ChildrenBased on the Second Model List of Essential Medicines for Children 2009世界卫生组织儿童标准处方集基于2009年儿童基本用药的第二个标准目录WHO Library Cataloguing-in-Publication Data:WHO model formulary for children 2010.Based on the second model list of essential medicines for children 2009.1.Essential drugs.2.Formularies.3.Pharmaceutical preparations.4.Child.5.Drug utilization. I.World Health Organization.ISBN 978 92 4 159932 0 (NLM classification: QV 55)世界卫生组织实验室出版数据目录：世界卫生组织儿童标准处方集基于2009年儿童基本用药的第二个标准处方集1．基本药物 2.处方一览表 3.药品制备 4儿童 5.药物ISBN 978 92 4 159932 0 (美国国立医学图书馆分类：QV55)World Health Organization 2010All rights reserved. Publications of the World Health Organization can be obtained fromWHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e-mail: ******************). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the aboveaddress(fax:+41227914806;e-mail:*******************).世界卫生组织2010版权所有。
超疏水材料研究意义及方法简介1、研究意义固体材料表面的润湿性是材料科学和表面化学中一个非常重要的特性，许多物理化学过程，如吸附、润滑、粘合、分散和摩擦均与表面浸润性密切相关[1-2]。
超疏水表面通常被定义为接触角大于150°，滚动角小于10°的表面[3]，这种独特的浸润性，使其在自清洁[4-5]、金属防腐[6-7]、防覆冰[8-9]、抗污染[10]、油水分离[11-12]、微流体装置[13-14]等领域具有巨大的应用价值。
近年来超疏水表面在基础研究和工业应用上发挥出巨大的影响，因此收到受到人们的广泛关注。
2、国内外研究现状受自然界中“荷叶效应”的启发，人们发现超疏水表面是由粗糙的微观形貌和疏水的低表面能物质共同决定的[15-16]。
这种特殊的结构有助于锁住空气，防止水将表面润湿，因此水滴在表面上形成球形。
近年来，人们基于此原理构造出很多仿生超疏水表面，主要分为以下两种途径：一种是对分级几何粗糙结构表面进行疏水化修饰；另一种是通过在疏水表面构造多级几何粗糙结构。
其中，低表面能的表面制作在技术上已经相当成熟，而微观几何粗糙度的构建才是构造超疏水表面的难点，目前国内外构造微纳粗糙结构的方法主要包括模板法[17]、相分离法[18]、刻蚀法[19]、化学气相沉积法[20]、溶胶凝胶法[21]、层层自组装法[22]、静电纺丝法[23]、印刷法[24]等。
例如，Zhou等[25]将十三氟辛基三乙氧基硅烷（FAS）、聚二甲基硅氧烷（PDMS）和FAS改性的二氧化硅溶解在己烷中，将织物浸泡其中，再取出于135℃固化30min，得到耐磨性、耐洗性、化学稳定性优异的超疏水织物。
Wang等[17]采用聚苯胺形成的水凝胶结构为模板，利用正硅酸乙酯的水解原位生成二氧化硅，再在表面沉积十八烷基三氯硅烷形成超疏水涂层，具有力学性能优异、透明、可拉伸等优点。
Sparks等[26]选用季戊四醇四（3-巯基丙酸酯）、三烯丙基异氰尿酸酯、2,4,6,8-四甲基-2,4,6,8-四乙烯基环四硅氧烷以及疏水二氧化硅粒子，利用一步喷涂法，在紫外光下发生巯烯点击反应形成有机-无机杂化交联涂层。
BaTiO 3/环氧防腐涂料的制备及性能研究摘要：防腐涂料是保证金属结构正常使用的重要材料，防腐涂料的开发和研究一直是涂料领域的热点方向。
研究使用BaTiO 3作为防腐功能填料，探讨其用量对环氧防腐涂料性能的影响，研究发现：当BaTiO 3粉体添加量为50wt.%时，涂料的中性盐雾时间超过280h ，漆膜的腐蚀电流低，腐蚀电位高，证明其具有良好的电化学防腐性能。
关键词：环氧树脂；BaTiO 3；盐雾实验；腐蚀电位中图分类号：O632文献标识码：A 文章编号：2095-0438（2021）06-0148-04（哈尔滨理工大学材料科学与化学工程学院黑龙江哈尔滨150001）防腐是在金属基材表面选用特种防腐材料对基材进行防护，使其避免受到外界因素带来的的化学腐蚀，据有关部门统计每年因腐蚀造成金属损失高达数亿元之巨。
因此对于防腐的研究一直是居高不下的热门方向[1]。
在防腐涂料体系中，富锌涂料是利用率较高的底漆[2]。
活性锌与铁基体形成腐蚀电偶，使铁的腐蚀电位被降低[3]。
但富锌涂层存在一些不足之处，锌粉之间、锌粉与金属基体之间的有效电接触是阴极保护的前提。
因此，锌涂料中锌粉的质量含量非常大，一般可达80~90wt%，大量锌的存在增加了涂层的孔隙率，使屏蔽效果受到破坏[4]。
有很多研究尝试在导电材料[5]或光电材料[6]中掺杂，如，碳黑[7]、石墨烯[8]、碳纳米管[9]、纳米TiO 2[10]等。
虽然这些研究取得了一定的改善，但在考虑涂层的腐蚀介质屏蔽方面还应该进一步探索。
钛酸钡作为广为人知的铁电体，有着很高的介电常数[12]，它在电场下发生的极化现象能引起其介电常数的明显变化，可以此作为增强其电化学性能的途径，从而提升对腐蚀介质的阻隔作用，延长涂料对金属基材的保护效果[13-16]。
于是本文采用BaTiO 3作为填料，加入到环氧树脂防腐涂料中，制成BaTiO 3/环氧树脂薄膜，探究BaTiO 3添加量对防腐性能的影响。
REVIEWCorrosion behavior of superhydrophobic surfaces: AreviewAdel M.A.Mohamed a,b,Aboubakr M.Abdullah a,c,*,Nathalie A.Younan aa Center for Advanced Materials,Qatar University,Doha2713,Qatarb Department of Metallurgical and Materials Engineering,Faculty of Petroleum and Mining Engineering,Suez University,Box43721,Suez,Egyptc Chemistry Department,Faculty of Science,Cairo University,Giza12613,EgyptReceived18January2014;accepted7March2014Available online24March2014KEYWORDS Superhydrophobic; Materials; Surfaces; Corrosion; Protection Abstract Superhydrophobic surfaces have evoked great interest in researchers for both purely aca-demic pursuits and industrial applications.Metal corrosion is a serious problem,both economically and operationally,for engineering systems such as aircraft,automobiles,pipelines,and naval ves-sels.Due to the broad range of potential applications of superhydrophobic surfaces,there is a need for a deeper understanding of not only how to fabricate such surfaces using simple methods,but also how specific surface properties,such as morphology,roughness,and surface chemistry,affect surface wetting and stability.In this article,a comprehensive review is presented on the researches and developments related to superhydrophobicity phenomena,fabrication of superhydrophobic surface and applications.A significant attention is paid to state of the art on corrosion performance of superhydrophobic coatings.ª2014King Saud University.Production and hosting by Elsevier B.V.All rights reserved.Contents1.Introduction (750)2.Superhydrophobicity phenomena in nature (751)3.The theory of superhydrophobic surfaces (752)3.1.Contact angle and the Young equation (752)*Corresponding author at:Chemistry Department,Faculty ofScience,Cairo University,Giza12613,Egypt.Tel.:+2097444035672;fax:+2097444033889.E-mail addresses:abubakr_2@,bakr@.qa(A.M.Abdullah).1878-5352ª2014King Saud University.Production and hosting by Elsevier B.V.All rights reserved./10.1016/j.arabjc.2014.03.0063.2.Rough surfaces and the Wenzel and Cassie-Baxter models (753)4.Fabrication of superhydrophobic surfaces (754)4.1.Sol–gel process (754)yer-by-layer self-assembly (755)4.3.Etching (755)4.4.Chemical and electrochemical deposition (756)4.5.Other techniques used (756)5.Applications of superhydrophobic surfaces (757)5.1.Anti-adhesion and self-cleaning (757)5.2.Anti-biofouling applications (757)5.3.Corrosion inhibition (757)5.4.Drag reduction (758)6.State-of-the-art studies on corrosion resistant coatings using superhydrophobic coatings (758)7.The stability of the superhydrophobic surfaces (759)7.1.Solvent stability (760)7.2.pH stability (762)7.3.Thermal and humidity stability (762)7.4.UV stability (762)References (763)1.IntroductionSuperhydrophobic surfaces have evoked great interest in researchers for both purely academic pursuits and industrial applications.Many review articles covering different aspects of superhydrophobicity have been published(Bhushan and Jung,2011;Ma and Hill,2006;Nakajima et al.,2001;Quere, 2005;Roach et al.,2008;Xue et al.,2010).Superhydrophobic surfaces(SHS)exhibit extremely high water repellency,where water drops bead up on the surface,rolling with a slight ap-plied force,and bouncing if dropped on the surface from a height.It is well known that the degree to which a solid repels a liquid depends upon two factors:surface energy and surface morphol-ogy.When surface energy is lowered,hydrophobicity is en-hanced.Chemical compositions determine the surface free energy and thus have a great influence on wettability (Woodward et al.,2000).However,certain limitations are encountered and superhydrophobic surfaces cannot be obtained only by lowering the surface energy.For example,the–CF3–ter-minated surface was reported to possess the lowest free energy and the liquid droplet.Since air is an absolutely hydrophobic material with a contact angle of180°,this air trapping will amplify surface hydrophobicity(Ogihara et al.,2013;Sun et al.,2005).Hierarchical micro-and nanostructuring of the surface is thus responsible for superhydrophobicity.Surface wetting behavior can generally be broken into4dif-ferent regimes,based on the value of water contact angle (WCA).The two most conventional regimes are the hydro-philic and hydrophobic regimes,defined as WCAs in the range of10°<h<90°and90°<h<150°,respectively.The hydrophobic coatings are intensively used in plenty of engi-neering applications,however;the hydrophilic coatings are widely used in paint and varnish industries.Although the applications of hydrophobic and hydrophilic regimes,the other superhydrophobic and superhydropholic regimes,which describe the extremes of surface wetting behavior,are wholly more interesting.Superhydrophilicity,which is characterized by WCAs in the range of h<10°,within1s of the initial wet-ting,describes nearly perfect wetting.In contrast,superhy-drophobicity,described by WCAs of h>150°,describes a state of nearly perfect non-wetting(Fig.1).In addition to high contact angles,superhydrophobic sur-contact angle(CA)for a water drop placed on surfaces of different hydrophobicities750 A.M.A.Mohamed et al.cleaning is the joint action of small adhesion of dust particles high capillary force acting on the dust par-drop–air interface.These properties arise from the low interfacial energy and their rough Barkhudarov et al.,2008).This combination leads to contact angles (WCAs)larger than 150°with and theself-cleaning effect.repellency and self-cleaning,other properties incorporated in superhydrophobic surfaces transparency and color (Fig.2),anisotropy,reversibil-breathability (moisture vapor transfer)).2.Superhydrophobicity phenomena in natureThe amazing water-repellency,superhydrophobicity,plants has received a great deal of interest.eral plants such as Nelumbo nucifera (Lotus),Fig.3,Brassica oleracea ,Colocasia esculenta as well as the wings of butterflies (Goodwyn the legs of water striders (Gao and Jiang,hydrophobic surfaces.Gao et al.(2004)showed that the unique ture of the water striders’legs,which are covered bers of oriented tiny hairs (microsetae)with Transparent super-hydrophobic thin film with TiO 2photocatalyst (Nakajima et al.,2001).(b)Colored Ishizaki and Sakamoto,2011).which exhibit extraordinary water repellency on their upper side.(b)Scanning prepared by ‘glycerol substitution’shows the hierarchical surface structure consisting tubules on the upper leaf side (Ensikat et al.,2011).responsible for their water resistance.The air trapped in spaces between the microsetae and nanogrooves leads to the superhy-drophobic property of the legs,with a contact angle found to be around167°.This allows water striders to survive on water.Bechert et al.(2000)showed that the shark skin is covered by very small individual tooth-like scales called dermal denti-cles(little skin teeth),ribbed with longitudinal grooves(aligned parallel to the localflow direction of the water).These grooved scales reduce the formation of vortices present on a smooth surface,resulting in water moving efficiently over their surface.Neinhuis and Barthlott(1997)reported the water contact angles of more than200plant species and investigated their surface morphologies.There are two different types of water-repellent plant leaves:thefirst type is hair covered leaves such as Lady’s Mantle,and the second type is macroscopically smooth leaves such as Lotus(Otten and Herminghaus, 2004).Water droplets completely run off both plants’leaves and their surfaces remain dry even after heavy rains.Although many plants have exhibited similar contact angles (around160°),the lotus leaves have shown better stability and perfection as water repellent.These observations have led to the concept of the‘‘Lotus effect’’and made out of the Lotus plant an archetype and an ideal model for superhydrophobic-ity.Some works made it obvious that the contact angle alone is not sufficient to compare the efficiency of superhydrophobic samples(Bechert et al.,2000;Ensikat et al.,2011;Neinhuis and Barthlott,1997).Many other factors interfere,such as the morphology of the epidermal structure(papillose or non-papillose surface),the nanoscopic epicuticular wax crystals of the leaves and the stability of the superhydrophobicity un-der moisture condensation conditions.Only the Lotus plant showed no significant loss of the water repellency property un-der these conditions.All in all,the unique shape of its papillae,the unique prop-erties of its epicuticular wax and its stable superhydrophobicity have made out of the Lotus leaf an outstanding model for the development of many superhydrophobic structures.3.The theory of superhydrophobic surfacesIn this section,the theory and fundamentals of wetting of a rough surface and the equations that govern the contact angle of a liquid are presented and discussed.3.1.Contact angle and the Young equationAtoms or molecules at the surface of solids or liquids possess fewer bonds with neighboring atoms than those in the interior, and thus,have higher energy.This surface energy or surface tension,c,is equal to the work required to create a unit area of the surface at constant pressure and temperature,and is measured in N/m.The values of surface tension of some mate-rials at20°C,found in the literature,are listed in Table1.As illustrated in Fig.4a,when a liquid drop is placed in contact with a solid,the equilibrium of the solid and liquid sur-faces will be established at a certain angle called the static con-tact angle CA,h0,given by the Young equation:cos h0¼cSAÀc SLcLAð1Þwhere c ,c and c are the surface energies of the solidliquid drop on a(a)smooth solid surface(Bhushan and Jung,2011)and(b)tiltedNosonovsky and Bhushan,2009).752 A.M.A.Mohamed et al.(<10°)in addition to high CA(>150°).As mentioned in the previous sections,a low CAH allows water to roll-off easily along the surface.Occurrence of contact angle hysteresis is associated with the surface defects,which could be from the surface roughness,chemical heterogeneity,or wetting state. According to the difference of contact angle hysteresis,sur-faces can perform as slippery or sticky surfaces.The pinning phenomenon during the evaporation of a droplet is an example of the contact angle hysteresis.The Young equation was based on the concept of an ideal-ized,atomically smooth solid surface.However,all surfaces have defects and imperfections that contribute to surface roughness, and this roughness will contribute to the surface wetting behavior(Patankar,2004).In view of this roughness-induced wettability modification,two well-established models have been developed to account for these effects:the Wenzel model (1936)and the Cassie-Baxter model(1944).3.2.Rough surfaces and the Wenzel and Cassie-Baxter models On rough surfaces,the Young equation no longer applies. Wenzel(1936,1949)proposed a model to describe the contact angle,h,with a rough surface,by relating it to that with aflat surface h0.He modified the Young equation as follows:cos h¼rc SAÀc SLc LA¼r cos h0ð2ÞThis is called the Wenzel equation,where r is the non-The Wenzel equation is only valid for the homogeneous so-lid–liquid interface shown in Fig.5a.It no longer applies for heterogeneous surfaces.Therefore,Cassie and Baxter(1944)proposed another mod-el for heterogeneous surfaces composed of two fractions,one with a fractional area f1and contact angle h1and the other with f2and h2,with f1+f2=1.The contact angle is thus given by: cos h¼f1cos h1þf2cos h2ð4ÞFor the case of a composite interface,shown in Fig.5b,the first fraction corresponds to the solid–liquid interface (f1=f SL;h1=h0)and the second fraction to the liquid–air interface(f2=f SL=1Àf SL;h2=180°).Combining Eqs.(2)and(4)gives rise to the Cassie&Baxter equation:cos h¼rf SL cos h0À1þf SLð5Þorcos h¼r cos h0Àf LAðr cos h0þ1Þð6ÞThe opposite limiting case with h2=0°,corresponding to the water-on-water contact when the rough surface is covered by holesfilled with water instead of air(Fig.5c),yields the Cassie equation:cos h¼1þf SLðcos h0À1Þð7ÞAccording to Eq.(6),for a hydrophobic surface(h0>90°), the contact angle increases with an increase of f LA leading thus, to a more hydrophobic surface.For a hydrophilic surfacedescribed by(a)Wenzel equation for homogeneous interface,(b)Cassie and BaxterCassie equation for the homogeneous interface(Nosonovsky and Bhushan,2009).Corrosion behavior of superhydrophobic surfaces753state are weaker than those in the Wenzel state(Koishi et al., 2011;Lafuma and Quere,2003;Dupont and Legendre,2010; Kong and Yang,2006).For example:Lafuma and Quere (2003)compared the CAH of water droplets in the cases of both Cassie and Wenzel states on the same microtextured sur-face.For the Cassie state,the water droplet was gently dis-pensed on the surface while,in order to maintain the Wenzel state,the water droplet was condensed onto the surface.In addition to a higher advancing CA,it was shown that the CAH was significantly lower in the case of the Cassie state. Koishi et al.(2011)used molecular dynamic simulations to elu-cidate the relationship between the values of the CAH and the corresponding wetting regime.They found that the CAHs,in the case of the composite Cassie state,are weaker in compar-ison with those in the homogenous wetting Wenzel state on the same structure.It may be concluded that,the Cassie model is a more gen-eral model that can be used to predict entire wetting regimes from low extreme to high extreme,whereas the Wenzel model can predict only moderate homogenous wetting regimes be-tween the two extremes.From the Cassie model,it can be no-ticed that a reduction in the solid fraction and an increase in the air fraction would enhance the water repellency of a sur-face regardless of whether the surface is hydrophobic or hydrophilic.4.Fabrication of superhydrophobic surfacesA variety of materials have been used to prepare superhydro-phobic surfaces including both organic and inorganic materi-als.For polymeric materials,which are generally inherently hydrophobic,fabrication of surface roughness is the primary focus.For inorganic materials,which are generally hydro-philic,a surface hydrophobic treatment must be performed after the surface structures are fabricated.Several techniques for the preparation of superhydrophobicinvestigated and reported.However,theyvided into two categories(Ma and Hill,2008;Xu et al.,2011):i.Making a rough surface from amaterial.ii.Modifying a rough surface with aface energy.Various methods are used for thesurfaces,such as mechanical stretching,layer-by-layer assembly,etching,electrochemical depositions and chemicalA brief description and use of some of theseniques are presented in the following4.1.Sol–gel processThe sol–gel process is an efficient,temperature/low pressure procedure andsurfaces on a variety of oxides.This approachprocess for the preparation ofmaterials.The roughness of the surfacecess can be easily modified simply byof the reaction mixture and the protocol coatings are the most used in the sol–gel method.Sol–gel pro-cesses can produce rough surfaces on a variety of oxides such as silica,alumina,and titania(Roig et al.,2004;Tadanaga et al., 1997).This approach is a very versatile process for the prepara-tion of superhydrophobic thinfilms or bulk materials.The sol–gel process can form aflat surface coating,xerogel coating or aerogel coating depending on the process conditions;both xerogel and aerogel show rough or fractal surfaces.Barkhudarov et al.(2008)used organo-trimethoxysilanes as starting materials to make optically transparent superhydro-phobicfilms with contact angles exceeding155°and reaching 170°.Xiu et al.(2008)generated superhydrophobic isobutyl surface groups by incorporating isobutyltrimethoxysilane (IBTMOS)into silica layers.With a TMOS/IBTMOS ratio of1:1,a contact angle of165–170°was observed.As shown in Fig.6,the obtained surface consists of globules(20–50nm in diameter)surrounding a network of pores(submicron size), which indicates a hierarchical roughness in two scales:nano-scale and submicron scale.Latthe et al.(2009)managed to prepare superhydrophobic silicafilms on glass substrates using trimethylethoxysilane as a co-precursor.The silicafilms obtained were transparent and stable to high temperatures(up to275°C)and humidity,hav-ing a water contact angle of151°and a sliding angle of8°.Feng et al.(2004)managed to grow superhydrophobic aligned ZnO nanorods starting from ZnO sol.Water contact angles exceeding160°were observed.These nanorodfilms exhibited a reversible behavior from superhydrophobicity to superhydrophilicity by alternation of ultraviolet irradiation and dark storage:after UV illumination for2h,the water con-tact angle drops from$160°to0°and returns to the initial va-lue after storage in the dark for7days.The reason for the reversible behavior is due to the generation of electron–hole pairs in the ZnO surface resulting from the UV irradiation, some of these holes can react with the lattice oxygen to form Figure6High resolution SEM image of a silicafilm with TMOS/IBTMOS ratio of1:1(Xiu et al.,2008).754 A.M.A.Mohamed et al.only the upper part of the nanorods not in contact with liquid. This effect results in a water CA of about0o(Sun et al.,2001; Bico et al.,2001).It should be stated that these superhydrophobic coatings synthesized using the sol–gel processing are usually stable due to the formation of covalent bonds between the coating and the substrate(Xue et al.,2010).The resulted coatings are robust and rough(Xiu et al.,2008).yer-by-layer self-assemblyThe layer-by-layer(LBL)assembly is a simple and cheap meth-od to construct thin-film coatings by depositing alternating layers,oppositely charged,with intermediate washing steps. It uses electrostatic interaction and covalent bonds to form multilayer grafts.The advantage of this technique is that it possesses a high degree of molecular control over thefilm thickness,which arises from the linear growth offilms with re-spect to the number of bilayers.Recently,LBL method has sponds to the number of deposition cycles.The resulting super-hydrophobic coatings on steel substrate exhibited a strong repulsive force to water droplets,with contact angles greater than165°.Fig.7illustrates water droplets on the three layers of TiO2nanoparticle coated surface and shows SEM images of one to three layers of P25on the steel surfaces.Zhai et al. (2004)also prepared a polyelectrolyte multilayer surface by LBL assembly and then overcoated the surface with silica nanoparticles to mimic the hierarchical scale present on lotus leaf surfaces.Superhydrophobicity was achieved after surface fluorination with afluoroalkyl silane.Amigoni et al.(2009)constructed hybrid organic/inorganic surfaces by alternating different layers of amino-functionalized silica nanoparticles and epoxy-functionalized smaller silica nanoparticles.They found out that the hydrophobicity in-creases with the number of layers and obtained a water contact angle around150°with the alternation of nine layers.LBL assembly could be combined as well with electrode-position to make superhydrophobic coatings as described by Zhao et al.(2005).images of different layers of TiO2nanoparticles in steel surface:(a)Water droplets on the treated steel)*1.(c)TiO2two layers(TiO2)*2and(d)TiO2three layers(TiO2)*3(Isimjan et al.,2012).Corrosion behavior of superhydrophobic surfaces755on the chemical etching time.A contact angle larger than150°was achieved at an etching time of more than3min.Pan et al.(2010)established a simple cetyltrimethylammo-nium bromide(CTAB)and ultrasonication assisted nitric acid HNO3etching technique to fabricate a rough surface on the copper substrate.A superhydrophobic coating was obtained with a contact angle around155°.Gao et al.(2012)fabricated a rough surface on the zinc sub-strate using a glow discharge electrolysis plasma(GDEP)reac-tor to etching.This apparatus consists of a high voltage supply unit and two electrodes submerged in an electrochemical cell separated by a dielectric wall with a diaphragm.Shiu et al.(2005)developed an approach for making tun-able superhydrophobic surfaces using oxygen plasma etching. Water contact angles up to170°were obtained.4.4.Chemical and electrochemical depositionChemical and electrochemical deposition techniques have been intensively employed to prepare superhydrophobic surfaces. Darmanin et al.(2013)reviewed the most published researches showing the details of electrochemical oxidation processes, such as oxidation of metals in solution,anodization of metals or electrodeposition of conducting polymers,and reduction processes,e.g.,the electrodeposition of metals and galvanic deposition.Ou et al.(2012)investigated the corrosion behavior in NaCl solution of superhydrophobic surfaces prepared by1H,1H, 2H,2H-perfluorooctyltrichlorosilane(PFOTS)chemically ad-sorbed onto the etched titanium substrate.It has been shown that the strong chemical interfacial bonding between PFOTS and Ti leads to a higher stability and corrosion inhibition effi-ciency.Yin et al.(2008)also prepared a stable superhydropho-bicfilm by mystic acid chemically adsorbed onto anodized aluminum substrate.The contact angle was in the order of 154°,and corrosion in seawater was significantly decreased.Huang et al.(2013)demonstrated that the copper surface covered with copper stearate,which was formed by an electro-chemical reaction with a DC voltage of30V in stearic acid solution,showed superhydrophobic properties.Shirtcliffe et al.(2004)electrodeposited copper from acidic copper sulfate solution ontoflat copper substrates to obtain superhydropho-bic surfaces of varying levels of roughness,depending on the current density during deposition.4.5.Other techniques usedOther approaches to the fabrication of superhydrophobic sur-faces have been developed and used,these include spraying nanoparticle suspensions onto substrates(Ogihara et al., 2013),chemical vapor deposition(Ishizaki et al.,2010),elec-trospinning(Acatay et al.,2004;Ma et al.,2005),sublimation (Nakajima et al.,1999),hydrothermal synthesis(Shi et al., 2005),and wax solidification(Onda et al.,1996).Spraying is a one-step,time-saving,low-cost and repairable method for preparation of superhydrophobic surfaces.Xu et al.(2011)fabricated superhydrophobic copper meshes by evenly spraying an emulsion of n-octadecanethiol and silver ni-trate in ethanol onto the copper mesh with nitrogen gas by a spray gun.Alkanethiols contain long-chain alkyl groups that have low surface free energy.One advantage of this method is that in the case of mechanical damage of the surface,it can simply be repaired by partial spraying.In a similar way, Ogihara et al.(2013)prepared superhydrophobic paper using mixtures containing nanoparticles and ethanol,manually sprayed over paper from20cm away with a vaporizer.In this case,the surface energy and the roughness structure could be controlled by the spray-coating conditions,such as the type of nanoparticles and their size.Electrospinning is another powerful,simple and practical one-step method to generate continuous ultrathinfibers with micrometer and sub-micrometer diameters from a variety of polymeric materials.Electrospunfibers intrinsically provide at least one length scale of roughness for superhydrophobicity because of the smallfiber size.Thefiber mats composed solely of uniformfibers could be obtained by electrospinning a hydrophobic material(i.e.,poly(styrene-block-dimethylsilox-ane)block copolymer)blended with homopolymer polystyrene (PS)(Ma et al.,2005).Table2shows the most important parameters controlling the electrospinning process.Acatay et al.(2004)electrospun a thermosetfluorinated polymer onto an aluminum foil substrate,by applying an elec-trical bias from the tip of the polymer solution-filled syringe to a grounded collection plate.The formed electrospunfilm con-sisted of a continuous web or mat of randomly alignedfibers.After the roughening of the surfaces,most substrates still do not show superhydrophobicity.Consequently,the surface energy of such coatings should be lowered using low surface energy materials.The most common ones arefluorocarbons, silicones,and some organic materials(polyethene,polystyrene, ...).Although,inorganic materials such as ZnO and TiO2have high surface energy,the nanoparticles from these materials are easily covered by airborne organic contaminations.Due to such contaminations the surfaces modified with such nanopar-ticle layers may demonstrate superhydrophobic behavior.For instance,fluoroalkylsilane(FAS)molecules were intensively used by several groups in order to modify the surface and en-hance superhydrophobicity due to their extremely low surface free energy and the simple reaction of the silane groups withTable2Most important electrospinning parameters(Sas et al.,2012).Materials properties Process parameters Equipment design Ambient conditions Viscosity Electricalfield strength Needle design Relative humidity Conductivity Solution charge polarity Collector geometry TemperatureSolvent volatility Electrical signal type Surrounding medium Surface tension Tip to collector distancePolymer MW Flow ratePolymer type Collector take-up velocity756 A.M.A.Mohamed et al.the hydroxyl groups on coatings(Hu et al.,2012;Ishizaki et al.,2011;Liang et al.,2013;Song et al.,2012).5.Applications of superhydrophobic surfacesThe impetus for the development of materials with superhydro-phobic properties is for use in practical applications.Superhy-drophobic surfaces have attracted growing interest in the past two decades because of their unique water repellency,self-clean-ing property and their importance in various applications, including self-cleaning windows,roof tiles,textiles,solar panels and applications requiring anti-biofouling and reduction of drag influid(micro/nanochannels)(Bhushan and Jung,2011). Some agricultural applications were also discussed,such as bio-medical applications(Xiu et al.,2007),stain resistant textiles (Satoh and Nakazumi,2003),ant-sticking of snow for antennas and windows(Kako et al.,2004)and many others.One of the most important applications for superhydrophobic surface is corrosion resistance for metals and alloys,and remains the most significant goal in this review.The following section includes how superhydrophobic coatings are used to improve the perfor-mance of some applications by surface modification.5.1.Anti-adhesion and self-cleaningAs previously mentioned,the high water contact angle(above 150°)and the low contact angle hysteresis of superhydropho-bic surfaces characterize them with low adhesion and self-cleaning properties that are extremely useful for practical applications such as self-cleaning window glasses.In a natural environment,surfaces get contaminated very easily and frequently.Cleaning them requires effort,time and money.Thus,the creation of substrates that are self-clean-ing and that have low-adhesion to contaminants has been a hot topic of research for several decades.As illustrated in Fig.8,when a water droplet rolls off a superhydrophobic sur-SiO2nanoparticles onto the etchedfilm.They showed that much of the red powder was still spread on the uncoated sur-face after cleaning with water droplets as compared to the superhydrophobic surface,which was much cleaner.More-over,dust particles were heavily sprinkled on the coated sur-face and were simply removed byflipping it,showing the anti-adhesion property for contaminants of suchfilms.Superhydrophobic surfaces with self-cleaning property also have many applications in the textile industry.For example, self-cleaning textile shirts,blouses,skirts and trousers,which are stain-proof,have already been synthesized(Xue et al., 2010).Furthermore,the self-cleaning effect is used in optical applications,such as solar panels,lenses and mirrors that have to stay clean(Nosonovsky and Bhushan,2009).5.2.Anti-biofouling applicationsBiofouling of underwater structures and ships’hulls,in partic-ular,increases operational and maintenance costs(Gudipati et al.,2005;Townsin,2003).It can be reduced through under-water superhydrophobicity,i.e.,forming a hydrophobic rough surface that supports an airfilm between itself and the water (Marmur,2006).The reduction of the wetted area minimizes the probability that biological organisms encounter a solid sur-face.The design of such surfaces should involve optimization between mechanical stability and minimal wetted area.The anti-biofouling properties of superhydrophobic coatings have been investigated(Zhang et al.,2005).Compared to normal substrates,which fouled within a day,almost no micro-organ-isms attached to the superhydrophobic surfaces in thefirst week after immersion.5.3.Corrosion inhibitionThe concept of preparing surfaces that repel water creates huge opportunities in the area of corrosion inhibition for metals and alloys.Given their water repellency,superhydrophobic coat-rolling off substrates with a normal hydrophobic surface(left)and a self-cleaningparticles(Xue et al.,2010).Corrosion behavior of superhydrophobic surfaces757。
