Interface-modulated morphological transition of biodegradable poly(ε-caprolactone) crystals†

Abstract

Poly(ε-caprolactone)(PCL)-based blends exhibit immense potential for the design of various environmentally friendly disposable or short-lived materials. The degradation of PCL components is determined by their crystallinity and crystal morphology, which is strongly correlated to the laboratory or industrial processing conditions of the blends. By using PCL/poly(t-butyl acrylate) (PtBA) mixed Langmuir monolayers as a model system, this study reports a striking interface-modulated morphological transition of PCL crystals, from highly branched symmetric dendrites, to six-arm dendrites, four-arm dendrites, seaweed-like crystals and distorted rectangular crystals. The results further demonstrate that the PCL chain folding reacts quickly to the change in the degree of undercooling (i.e., surface pressure), which controls the overall crystal morphologies through the interplay of the diffusion coefficient, surface tension, and surface tension anisotropy.