Preparation of responsive bilayer membrane through morphological tuning of nano-scale building blocks

Abstract

As society strives for automated systems, demand for novel smart materials is ever increasing. Typically, smart materials are designed based on structural gradient or contrasting material compositions. Here we have demonstrated the preparation of responsive bilayer membranes based on morphological tuning of nanoscale building blocks. The macroscopic membrane prepared using self-assembling V₂O₅ nanosheets and nanobelts shows contrasting mechanical and chemical properties. The contrasting membranes of V₂O₅ nanosheets and nanobelts were combined to prepare bilayer membranes that can sense environmental stimuli such as solvent vapors, humidity, and light and respond to them by changing their shape. Remarkably, the direction of the bending movement of the bilayer membrane is found to be selective towards the nature of the solvent vapors. In order to further improve the performance, the nanosheet section of the bilayer membrane was coated with MoS₂ through a microwave assisted synthesis method. Introduction of MoS₂ drastically improved bending and recovery speeds, conserving the selectivity towards the solvent vapors.