Free-standing polypropylene porous thin films using energy efficient coating technique

Abstract

Amongst various techniques to prepare thin films, spin coating takes less time to make thin films, is less energy-intensive, is easier to use, and provides reproducible results quickly. It is observed that such a user-friendly and quick process has hardly been explored to prepare polyolefin-based free-standing porous or nonporous thin films. Herein, we report a free-standing thin film of at least 5μm made from polypropylene using the spin coating technique. Our methodology utilizes lower embodied energy and generates lower carbon footprints than the conventional melt extrusion technique. The thin films prepared from the spin coating technique was investigated with DSC, XRD, SEM, XPS, etc., which suggested the heated thin films showed more crystallinity and strength compared to unheated thin films. The SEM images revealed a fibrous structure with a pore size range from 1-10μm. The tensile strength and modulus of the as-prepared thin films were found to be 7 MPa and 583 MPa, respectively. Also, enthalpy change of 84 J/g and relative crystallinity of 41% were obtained. The as-prepared thin film can be used in various applications with minor modifications, such as in coating layers on the solid surface, porous sorbent, and filtration membrane.