Polyamide composite membranes synthesized by conventional interfacial polymerization (IP) have attracted much attention for desalination to overcome the water shortage crisis. A big challenge is remained to desirably tune the thickness of polyamide nanofilms in these composite membranes by the uncontrollable IP process. Herein, we report a rational strategy to linearly regulate the nanofilm thickness from 32.3 to 5.6 nm by using glycerol as a water soluble and environment friendly additive to make the IP process controllable. The synthesized nanofilms display tuneable cross-linking degree and pore size, endowing the polyamide membranes with desirable water permeability and salt selectivity. Our membranes exhibit a rise of 51% in water permeance and keep the rejection ratio to Na₂SO₄ above 99.4% when the nanofilm thickness decreases from 32.3 to 15.1 nm. This strategy opens an eco-friendly and scalable avenue for synthesizing polyamide nanofilms which are deeply needed for nanofiltration, reverse osmosis and forward osmosis.

通过常规界面聚合（IP）合成的聚酰胺复合膜已受到海水淡化技术的关注，以克服水资源短缺的危机。通过不可控制的IP工艺来理想地调节这些复合膜中聚酰胺纳米膜的厚度仍然是一个巨大的挑战。本文中，我们报告了一种合理的策略，可以通过使用甘油作为水溶性和环境友好型添加剂来使IP工艺可控，从而将纳米膜的厚度从32.3线性调节至5.6 nm。合成的纳米膜显示出可调节的交联度和孔径，使聚酰胺膜具有所需的透水性和盐选择性。我们的膜的透水率提高了51％，并保持了对Na ₂ SO ₄的排斥率当纳米膜的厚度从32.3 nm减小到15.1 nm时，该值超过99.4％。该策略为合成纳米过滤，反渗透和正向渗透急需的聚酰胺纳米膜开辟了一条生态友好且可扩展的途径。