Abstract Unique anti-trade-off behavior, i.e., the concomitant increasing of water permeability and water selectivity, was observed in the nanocomposite membranes developed from polyvinyl alcohol incorporated with poly(2-hydroxyethyl methacrylate)-grafted silica nanospheres (PVA/PHEMA-grafted SNSs). Under a certain temperature range (10–30 °C) for the pervaporation dehydration of acetone-water solution, increasing of the grafted-PHEMA amount promoted extensively the anti-trade-off behavior as raising temperature. This is because the grafted-PHEMA on SNSs significantly enhanced the water permeability while efficiently limited the permeability of acetone. The characterization of the membrane free volume obtained from PALS suggests clearly that the promoted anti-trade-off behavior in PVA/PHEMA-grafted SNSs nanocomposite membranes were achieved due to a combined effect from the water-selective free volumes and their increasing number. In other word, the former contributes particularly to the improvement of water selectivity while the latter attributes to the enhancement of the water permeability.

中文翻译：

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促进聚乙烯醇 (PVA) 纳米复合膜的渗透选择性反折衷行为

摘要 在由聚乙烯醇与聚甲基丙烯酸 2-羟乙酯接枝二氧化硅纳米球（PVA/PHEMA 接枝SNS）。在丙酮-水溶液渗透蒸发脱水的一定温度范围（10-30°C）下，接枝PHEMA量的增加广泛促进了温度升高的反折衷行为。这是因为 SNS 上接枝的 PHEMA 显着增强了水的渗透性，同时有效地限制了丙酮的渗透性。从 PALS 获得的膜自由体积的表征清楚地表明，由于水选择性自由体积及其数量增加的综合作用，在 PVA/PHEMA 接枝的 SNS 纳米复合膜中实现了促进的抗权衡行为。换言之，前者特别有助于提高水的选择性，而后者则归因于透水率的提高。