When self-assembly meets interfacial polymerization

Abstract

Interfacial polymerization (IP) and self-assembly are two thermodynamically different processes involving an interface in their systems. When the two systems are incorporated, the interface will exhibit extraordinary characteristics and generate structural and morphological transformation. In this work, an ultrapermeable polyamide (PA) reverse osmosis (RO) membrane with crumpled surface morphology and enlarged free volume was fabricated via IP reaction with the introduction of self-assembled surfactant micellar system. The mechanisms of the formation of crumpled nanostructures were elucidated via multiscale simulations. The electrostatic interactions among m -phenylenediamine (MPD) molecules, surfactant monolayer and micelles, lead to disruption of the monolayer at the interface, which in turn shapes the initial pattern formation of the PA layer. The interfacial instability brought about by these molecular interactions promotes the formation of crumpled PA layer with larger effective surface area, facilitating the enhanced water transport. This work provides valuable insights into the mechanisms of the IP process and is fundamental for exploring high-performance desalination membranes.

Empowering ultrathin polyamide membranes at the water–energy nexus: strategies, limitations, and future perspectives

“…The creation of defect-free ultrathin polyamide membranes with highly cross-linked network structures, which are desired for achieving high ionic and molecular selectivity, has been made possible through a number of novel techniques, but producing defect-free membranes across large areas is still quite challenging. For instance, surfactant molecules are frequently employed to create uniform, defect-free sub-nanometer pores in PIP-TMC 13,14 and MPD-TMC 170,171 based membranes for precise ion and solute separation. In addition, by creating the top polyamide selective layer with an asymmetrical structure, it is possible to significantly enhance the selective separation of ions or solutes.…”

Self-assembly morphology transition mechanism of similar amphiphilic molecules

“…Overall, the development of molecular self-assembly is not only beneficial to the preparation of nanomaterials but also aids in the development of other research fields. 6–11 However, how far can we push molecular self-assembly? 12 What if one can use molecular self-assembly to build functional nanomaterials like Legos?…”

Water‐Assisted Programmable Assembly of Flexible and Self‐Standing Janus Membranes

“…Moreover, the transport/response performance of Janus membranes is closely linked to the wettability differentiation on opposite sides and the surface patterns. [ 2 , 6 , 7 , 8 ] The regulation of the wettability asymmetricity is hard to be reached technically in traditional methods. [ 2 ] Orderly patterns on the membrane surface can bring about abundant high‐permeability sites and large surface areas to accelerate the mass transport, [ 6 , 7 , 8 ] which still faces a great difficulty since their emergence requires special thermodynamic non‐equilibrium reaction processes.…”

“…[ 2 , 6 , 7 , 8 ] The regulation of the wettability asymmetricity is hard to be reached technically in traditional methods. [ 2 ] Orderly patterns on the membrane surface can bring about abundant high‐permeability sites and large surface areas to accelerate the mass transport, [ 6 , 7 , 8 ] which still faces a great difficulty since their emergence requires special thermodynamic non‐equilibrium reaction processes. [ 6 ] Developing a facile‐to‐scale‐up approach to fabricate Janus membranes with orderly surface patterns and desirable asymmetric wettability is therefore of vital significance for accessing ultra‐rapid transport/response efficiency.…”

“…As a typical thermodynamic non‐equilibrium process at immiscible liquid‐liquid diphase system, moreover, liquid‐liquid interfacial synthesis strategy can endow membranes with orderly surface patterns. [ 6 , 7 , 8 , 9 , 10 ] Up to now, however, the typical membranes prepared through liquid‐liquid interfacial assembly are symmetric membranes, and it is still a challenge for constructing Janus membranes possessing orderly patterns based on this strategy. Inspired by the fact that different nanostructures can be accessed from the same synthon under kinetical or thermodynamical control over the assembly pathway, [ 12 , 13 , 14 ] it's of high feasibility for constructing asymmetric membranes if we differentiate the assembly pathway in the immiscible two phases during the interfacial assembly process in the immiscible two phases to construct asymmetric membranes.…”