Photoresponsive Electrospun Polycaprolactone Nanofibrous Structure Embedding Dithienylethene Molecules

Abstract

Photochromic polycaprolactone (PCL) nanofibers were prepared through electrospinning. Various factors, including the solvent system, the concentration of PCL, the viscosity of the solution, and the electrical conductivity, influence the morphology of PCL nanofibers. A binary solvent system can dissolve PCL, control fiber structure and morphology, and allow solvent evaporation. The photochromic properties of electrospun membranes based on PCL and diethienylethene (DTE) were assessed using the CM-3610a spectrophotometer. The study showed that incorporating DTE into the membrane enables photochromic performance, with the photochromic reaction being reversible. The analysis of the color-change kinetics showed that the mechanism of photo cycling during colorization was linked to the amplitude of the fast and slow mechanisms, which depended on the formulation tested. The study showed that the photoreversion of the membrane under visible illumination occurs according to first-order kinetics. This work presented the design and manufacturing of photochromic membranes through electrospinning, which offers rapid color change rates, adjustable color fade times, superior reversibility, and reproducibility over at least 10 cycles. The thermochromic properties are proportional to the DTE concentration used, making it possible to obtain color variations with a delta E of 13 and 38 for concentrations ranging from 0.95 to 11.4 wt.%.