Cross‐linked polydimethylsiloxane (PDMS) is simultaneously water‐repellent and highly permeable to water vapor. Unfilled and silica‐free cross‐linked PDMS films of variable thickness (8–160 µm) are prepared and their water vapor transmission rates and permeability values are determined. Vapor transmission rate increases as membrane thickness decreased from 160 to 15 µm, but does not increase further when the film thickness is decreased to 8 µm. Rate‐limiting sorption is implicated as the cause of this effect and substantiated by a surface modification to enhance adsorption rate. Water vapor does not macroscopically condense on films thin enough to operate in this kinetic regime, and vapor transmission rates as high as 60% of the transmission rates through air are measured. A mechanism for water permeation is offered based on those proposed for nanoscopically confined water in carbon nanotubes and aquaporins.

中文翻译：

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重新发现有机硅：“疏水性” PDMS的反常水渗透性表明纳米结构及其在水净化和防冰中的应用

交联的聚二甲基硅氧烷（PDMS）同时具有拒水性和高水蒸气渗透性。准备了未填充且无二氧化硅的可变厚度（8–160 µm）的交联PDMS膜，并确定了它们的水蒸气透过率和渗透率值。蒸气透过率随着膜厚从160减小到15 µm而增加，但是当膜厚减小到8 µm时不会进一步增加。限速吸附被认为是造成这种效应的原因，并通过表面改性来提高吸附速率而得到证实。水蒸气在宏观上不会凝结在足够薄的薄膜上以在该动力学状态下运行，并且测得的蒸气透过率高达通过空气的透过率的60％。