Phase-Transition-Induced Turing Wrinkling Structures Enable Hierarchical Regulation of Polyamide Nanofiltration Membranes

Abstract

Turing patterns, arising from reaction-diffusion instabilities, provide a fundamental framework for understanding morphogenesis in nonequilibrium systems. Although Turing-like morphologies have been reported in polyamide (PA) nanofiltration (NF) membranes, current studies mainly rely on chemical regulation of reaction−diffusion processes, while the use of external physical stimuli remains largely unexplored. Here, we report a thermoresponsive strategy that triggers Turing patterns through polymer phase transition during interfacial polymerization (IP). Poly(N-isopropylacrylamide) (PNIPAM) is introduced into a piperazine (PIP)-trimesoyl chloride (TMC) IP system. By tuning the reaction temperature across the lower critical solution temperature (LCST) of PNIPAM, the polyamide layer transforms from a dense morphology into a periodic wrinkled structure. This thermoresponsive process reconstructs local mass transport and reaction kinetics, shifting the system from a diffusion-controlled regime to a reaction−diffusion-coupled regime and thereby triggering Turing instability. Experimental and simulation results reveal the mechanism of thermally induced Turing structure formation. This work demonstrates a thermoresponsive route to trigger Turing instability in PA membranes, establishing thermal responsiveness as an effective means to regulate reaction−diffusion dynamics and direct nonequilibrium morphological evolution.