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Shabanian, Sadaf

University of British Columbia

Liquid-repellent textile finishes have attracted considerable academic and industrial attention in recent years. These surfaces have broad applications in industries such as oil/water separation, stain resistance, anti-fouling, self-cleaning, textiles, and biomedicine. Perfluorinated substances are the most promising compounds for imparting durable water or oil repellency to textiles. However, these substances are persistent and bioaccumulate in the environment for thousands of years. Due to existing health and environmental concerns, environmental agencies have issued regulatory bans that will lead to their complete phase-out in the near future. Consequently, it is necessary to explore alternative liquid-repellent compounds with minimal toxicity. For decades, non-fluorinated surface chemistries were reported to exhibit zero or insignificant oil-repellency without fluorination. In this research, we develop design parameters for fabricating oil-repellent textile finishes using non-fluorinated surface chemistries. We introduce the first fluorine-free water and oil-repellent textile finish on a nylon jacket fabric using polydimethylsiloxane polymer brushes through a vapor deposition technique. The wettability equations utilized in this study suggest that, in theory, it is feasible to achieve durable oil repellency on a textured surface decorated with a smaller length scale texture on each fiber when the texture size, spacing and surface chemistry are properly controlled. The wettability equations are typically defined for a one-dimensional structure of the fabric while even monofilament fabrics have a three-dimensional structure. In this thesis, we examine a variety of monofilament and multifilament fabrics to evaluate the apparent contact angle and the breakthrough pressure of textured surfaces treated with a non-fluorinated surface chemistry for a range of low surface tension liquids. The accuracy of the existing theory in anticipating these values is explored. In an alternative approach to explore liquid repellent finishes, we apply perfluoropolyether polymer brushes to a nylon fabric using a single dip-coating method. The resulting coating exhibits robust water and oil repellency comparable to long-chain fluorinated finishes while its longest degradation byproduct is an ultra-short chain perfluorinated compound. Although further research is needed to determine the toxicity of its byproducts, perfluoropolyether-treated nylon exhibits superior wetting properties when compared to the short-chain perfluorinated compounds currently used in industry.

Text

2024-03-11

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87550

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/