Main transition-like feature in polylactic acid langmuir films

Polylactic acid is a simple polymer that has attracted interest, many years ago, as a biocompatible and biodegradable material for temporary implants and sutures that disintegrate gradually with time in vivo. Recently, it is also promoted as environmentally benign polymer for mass applications, e.g., packing film. We report about a phase transition in the monolayers, at the water–air interface, that looks and behaves similar to the main transition of monomer compound monolayers. We investigate the temperature dependence and the molecular weight dependence of this transition as well as how it is shifted in two component films, fabricated from mixtures of materials with different molecular weight. These results suggest that polylactic acid may not only be useful as a structural, passive material but that it also might be useful as a stable component of artificial active biological systems.