Добірка наукової літератури з теми "Textiles superhydrophobes"

Engineering of superhydrophobic textile surfaces has gained significant scientific and industrial interest for its potential applications in outdoor wear and protective textiles, resulting in many publications especially on theoretical models and fabrication methods. In this review, progress in theoretical definitions to explain the wetting behavior and realization techniques for superhydrophobic textile surfaces is discussed. Firstly, theoretical models from Young, Wenzel, and Cassie-Baxter to the more recent re-entrant angle model are overviewed to understand the design strategy for superhydrophobic surfaces. Secondly, major surface manipulation techniques to produce superhydrophobic textiles were reviewed for: modification of surface energy, addition of surface roughness by depositing or growing nanoparticles either in spherical form or in high aspect ratio, etching by plasma or caustic chemicals. Particular attention is paid to evaluation methods to measure the level of hydrophobicity for superhydrophobic textile surfaces, as a limitation of static water contact angle (WCA) on differentiating superhydrophobic surfaces has been reported elsewhere. The challenges in application of superhydrophobic textiles to clothing materials in terms of comfort properties and durability are discussed with the suggestion of further research opportunities to expand the application.

General information concerning different kinds of chemical additives used in the textile industry has been described in this paper. The properties and applications of organofunctional silanes and polysiloxanes (silicones) for chemical and physical modifications of textile materials have been reviewed, with a focus on silicone softeners, silane, and silicones-based superhydrophobic finishes and coatings on textiles composed of silicone elastomers and rubbers. The properties of textile materials modified with silanes and silicones and their practical and potential applications, mainly in the textile industry, have been discussed.

A superhydrophobic complex coating for cotton fabrics based on silica nanoparticles and new fluoroalkylsiloxane polymer was reported here. The complex thin film was prepared through sol-gel method using cotton fabrics as a substrate. Silica nanoparticles in the coating made the textile surface much rougher, and new fluoroalkylsiloxane polymer with reactive groups on the top layer of the surface lowered the surface free energy and enhanced the binding between silica nanoparticles and the fluoro-containing polymer. Textiles coated with this coating showed excellent water repellent property, and water contact angle (CA) increased from 138° on the pure fluoroalkylsiloxane polymer treated cotton fabric up to 156.5° on complex one. Moreover, this superhydrophobic complex coating possesses favorable washing durability and its CA still retain 106° after 20 times of soaping operations.

ZnO/SiO2 core/shell particles were fabricated and coated on poly (ethylene terephthalate) (PET) textiles, followed by hydrophobization with hexadecyltrimethoxysilane, to achieve superdrophobic surfaces with UV-shielding property. Transmission electron microscopy (TEM) was employed to reveal the fabrication of ZnO/SiO2 core/shell particles. Scanning electron microscopy (SEM) was conducted to investigate the surface morphologies of the textile and the coating of the fibers. UV-Vis spectrophotometry and contact angle measurement indicated that the incorporation of ZnO onto fibers imparted UV-blocking property to the textile surface, while the coating of SiO2 shell on ZnO made the superhydrophobicity of the as-treated PET textile surface UV-durable.

Superhydrophobic and transparent surfaces on cotton fabrics have been developed using silica nanomaterials. Initially, trichlorododecylsilane was treated on the silica nanoparticles to lower the surface energy of the fabric. By simply spraying alcohol suspensions containing hydrophobized silica nanoparticles, extremely water repellent coatings were formed on the textile fabrics. The effect of three types of alcohol solvent on the hydrophobicity of the coated cotton fabrics was examined by measuring the surface wettability. The treated cotton textiles in methanol exhibited contact angles higher than 160°, contact angle hysteresis lower than 10°, and good water repellency. It proved to be essential to form hierarchical morphology in achieving superhydrophobicity.

We report a facile and practical approach to fabricate versatile superhydrophobic and photocatalytic films from TiO₂–SiO₂@PDMS hybrids. The as-prepared hybrids can be applied to functional superhydrophobic textiles, treatment of dye waste water and water-repellent coatings.

Hydrophobic polydimethylsiloxane based coatings were self-roughened on poly(ethylene terephthalate) textiles via a nonsolvent-induced phase separation method to fabricate superhydrophobic and superoleophilic surfaces. The method is simple and large-area scalable and the obtained textiles could be used as excellent filters for continuous oil–water separation.

L'industrie textile s’intéresse depuis longtemps aux propriétés superhydrophobes et auto-nettoyantes. Le dépôt de composés fluorés à longues chaînes carbonées à la surface des textiles est actuellement le moyen le plus efficace d’obtenir de telles propriétés. En raison de leurs effets néfastes sur la santé et l'environnement, ces composés doivent être remplacés conformément à la réglementation REACH. Dans cette thèse, la polymérisation plasma a été choisie pour concevoir des traitements de surface durables, superhydrophobes et respectueux de l'environnement pour textiles. Dans ce contexte, la possibilité de contrôler temporellement et spatialement la cinétique de polymérisation plasma d'un précurseur modèle largement étudié à l'IS2M, à savoir l'anhydride maléique, a été démontrée dans un réacteur original d'un mètre de long. De plus, la possibilité de contrôler les propriétés chimiques et morphologiques des films polymères a été abordée. Suivant une méthodologie expérimentale similaire, le contrôle de la polymérisation plasma d'un précurseur organosiliconé, à savoir l’hexaméthyldisiloxane (HMDSO) a été étudié pour obtenir un revêtement superhydrophobe vert. L'accent a été mis sur la compréhension de la résistance au lavage de ces revêtements en caractérisant la cohésion du revêtement et de son adhérence à la fibre. Enfin, un second précurseur non fluoré a été testé en tant qu’alternative innovante à l’HMDSO. En contrôlant finement les paramètres temporels et spatiaux de la décharge plasma, les performances de superhydrophobie des polymères plasma et leurs durabilités ont pu être modifiées, soulignant l’approche tout à fait pertinente développée dans ce travail de thèse
The textile industry has been interested for long in water-repellency and self-cleaning properties. Deposition of fluorinated compounds with long carbon chains on the surface of textiles is currently the most efficient solution to reach such properties. Because of their harmful effects on health and environment, these chemicals have to be replaced in accordance with REACH specifications. During this PhD work, plasma polymerization process has been chosen as a good candidate to engineer durable, superhydrophobic and eco-friendly surface treatments for textiles. In this context, we successfully demonstrated the possibility to control temporally and spatially plasma polymerization kinetics of a model precursor widely studied at the IS2M, namely maleic anhydride, in an original one-meter long reactor. More than that, the possibility to control the chemical and morphological properties of plasma coatings was particularly addressed. Following a similar experimental methodology, the control of plasma polymerization of an organosilicon precursor, namely hexamethyldisiloxane (HMDSO), was investigated to get eco-friendly superhydrophobic coating. A focus was made on the understanding of thin film resistance to washing by characterizing coating cohesion and adhesion to the textile fiber. Finally, a second fluorine-free precursor was tested as an innovative alternative to HMDSO to engineer eco-friendly superhydrophobic coatings. By a fine tuning of temporal and spatial parameters of the plasma discharge, water-repellency performances of plasma polymer coatings and their durability could be significantly modified, highlighting the interesting approach developed during this PhD work

Water repellent fabrics with superhydrophobic properties have been constructed during this diploma work. First the fabrics were woven using six different weft yarns creating micro roughness and then a nanoparticle and surface energy lowering treatment was made. Contact angle measurements, contact angle hysteresis measurements, roll-off angle measurements and spray tests were made on the fabrics to investigate the hydrophobicity and water repellence. Also the durability was tested to examine the fastness of the treatments. It was found that the nanoparticles boosted the hydrophobicity of the hydrophobic treatments. Also by varying the size of textile filaments in yarns, the hydrophobicity of the material was affected. In this study, it was found how small textile parameters in the fabric could be changed to increase both durability and water repellence.
Program: Textilingenjörsutbildningen

Superhydrophobic surfaces have been widely explored by the scientific community and commercial market due to their remarkable properties as these surfaces are expected to repel water and show self-cleaning properties. These surfaces induce the beading of water drops, repelling them and dragging the accumulated dirt on the surface with them. This kind of surfaces has a wide range of applications. The present study is the result of a partnership between a private company, Extermínio, and the R&D centre, CQM (a National Research Laboratory). The goal of this partnership was the development of a superhydrophobic coating that could be applied to already existing surfaces, namely textiles and commercial glass, in order to turn them into superhydrophobic surfaces with the aim of making them easier to clean and increasing their durability, consequently decreasing the chemical products consumption used in those processes. For textiles, the selected samples were table linen, namely 100% cotton samples, both white and coloured and 50%/50% polyester/cotton coloured samples, and for commercial glass samples, flat glass was chosen. Different variables were considered when developing the coating solutions: pre-treated (chemically etched) and non-treated surfaces; different formulations but all silica-based (SiO2 10nm, SiO2 20nm and SiO2-PDMS); diverse solvents system; different concentrations; coating methods (dip coating and spray coating); number of coating layers; durability of the coatings (1hour, 24hours and 2 months) and contact angle measurements (24hours and 2 months). The different variables tested showed distinct results on both type of samples, but regarding the nanoparticles used, the SiO2-PDMS nanoparticles were the ones that revealed the best results. Lasting hydrophobic results were achieved for both type of samples (θ≥126°) which is an indicator that these coatings will ease the cleaning process and increase the durability the surfaces. No superhydrophobicity was attained (θ=180°), and therefore no self-cleaning property is expected from these coatings. The accomplished results are promising. More tests should be performed to understand the relationsip between the surface and the applied coatings. The first part of this dissertation is the presentation of the project framework and motivation that lead to its development as well as the intended goals. The work methodology and its structure are also briefly explained. The second part is dedicated to the theoretical introduction, in order to facilitate the concepts perception of this subject, starting with the historical perspective of superhydrophobic surfaces and its applications, as well as theoretical concepts as wettability and contact angle, surface roughness, contact angle hysteresis and measurements, as well as the creation of superhydrophobic surfaces. On the third part, the materials and methods applied to the development of the laboratory activities are described. The forth part is dedicated to explaining the choices of approach and also the presentation of the obtained results and its interpretation. Lastly, the fifth part is about the conclusions of the present work, as well as the learning’s and main difficulties found and some suggestion about future work that could be done to follow up the study carried out in this essay.
As superfícies superhidrofóbicas têm sido amplamente exploradas pela comunidade cientifica e pelo mercado devido às suas notáveis propriedades, nomeadamente por estas superfícies repelirem a água e apresentarem propriedades de autolimpeza. Superfícies deste tipo induzem a contração das gotas de água repelindo-as e arrastando consigo a sujidade acumulada nas superfícies. O presente estudo é o resultado de uma parceria entre uma empresa privada, a Extermínio, e o Centro de I&D, CQM (Laboratório de Investigação Nacional), com o objetivo de desenvolver um revestimento superhidrofóbico que possa ser aplicado em superfícies já existentes, nomeadamente têxteis e vidro comercial, de modo a transformá-las em superfícies superhidrofóbicas e torná-las mais fáceis de limpar. Aumentando por isso a sua durabilidade e, consequentemente, diminuindo o consumo de produtos químicos utilizados nestes processos. Para os têxteis, as amostras selecionadas foram toalhas de mesa, nomeadamente amostras de 100% algodão, tanto brancas como coloridas, e de 50%/50% poliéster/algodão coloridas, e para as amostras de vidro comercial foi escolhido o vidro plano. Foram testadas diferentes variáveis aquando do desenvolvimento das soluções de revestimento: superfícies pré-tratadas (quimicamente cauterizadas) e não tratadas; diferentes formulações porém todas à base de sílica (SiO2 10nm, SiO2 20nm e SiO2-PDMS) diferentes sistemas de solventes; diferentes concentrações; diferentes métodos de revestimento (por imersão e por pulverização); número de camadas de revestimento; durabilidade dos revestimentos (1 hora, 24 horas e 2 meses) e medição de ângulos de contacto (24 horas e 2 meses). As diferentes variáveis testadas mostraram resultados distintos em ambos os tipos de amostras. No que toca às nanopartículas utilizadas, as nanopartículas de SiO2-PDMS foram as que revelaram os melhores resultados. Foram obtidos resultados hidrofóbicos duradouros para ambos os tipos de amostras (θ≥126°), o que é um indicador de que estes revestimentos irão facilitar o processo de limpeza e aumentar a durabilidade das superfícies. Não foi alcançada superhidrofobicidade (θ=180°) e, portanto, não foi esperada nenhuma propriedade autolimpeza destes revestimentos. Apesar dos resultados alcançados terem sido promissores para uma aplicação comercial deverão ser realizados mais testes para compreender a relação entre a superfície e os revestimentos aplicados e melhorar a formulação e o tratamento das superfícies. A primeira parte desta dissertação é constituída pela apresentação da estrutura do projeto e da motivação que levou ao seu desenvolvimento, bem como os objetivos definidos. A metodologia do trabalho e o seu enquadramento são também brevemente explicados. A segunda parte é dedicada à introdução teórica, de forma a facilitar a compreensão dos conceitos apresentados, partindo de uma perspetiva histórica das superfícies superhidrofóbicas e as suas aplicações, bem como os conceitos teóricos como molhabilidade e angulo de contacto, rugosidade da superfície, histerese do angulo de contacto e medições, bem como a criação de superfícies superhidrofóbicas. Na terceira parte, estão descritos os materiais e métodos aplicados no desenvolvimento das atividades laboratoriais descritas. A quarta parte é dedicada a explicar as abordagens escolhidas, assim como a apresentação dos resultados obtidos e sua interpretação. Finalmente, na quinta parte são apresentadas as conclusões do trabalho, bem como as aprendizagens e principais dificuldades encontradas e algumas sugestões para futuros trabalhos a desenvolver neste estudo.

Superhydrophobic surfaces, especially lotus leaf surface, have been largely explored due to their great importance in fundamental research and abundant potential applications. However, many efforts have been focused on investigating the superhydrophobic surfaces in air instead of in water environment, which are rather crucial to industrial separation progress. A novel air bubble bursting effect on lotus leaf surface was firstly discovered and the underlying mechanism was believed to be related to the micro/nano-hierarchical rough structures. Inspired by air bubble bursting effect on lotus leaf, a superhydrophobic “artificial lotus leaf” with similar micro/nano-hierarchical rough structures was successfully constructed by photolithography and wet etching and also achieved air bubble bursting effect. Smooth and rough silicon surface with the ordered nano-structure or patterned micro-structure were utilized to study the contribution of the micro/nano-hierarchical structures to air bubble bursting, and it was found that air bubble could burst on the superhydrophobic surfaces with micro-structure, but more time was required, while nano-structure could accelerate air bubble bursting. Moreover, the height, width, and spacing of hierarchical structures also affected air bubble bursting, and the effect of the height was more obvious. When the height of hierarchical structures was around the height of lotus papillae, the width and spacing were significant for air bubble bursting. Eventually, an original model was proposed to further evaluate the reason that the micro/nano-hierarchical rough structures had an excellent air bubble bursting effect, and its validity was theoretically demonstrated. It was believed that these findings should spark further theoretical study of some bubble-related interfacial phenomena and find its wide applications in the industrial separation process without any accessional energy and other additives, such as mineral flotation, food processing, textile dyeing, and fermentation.