Swelling of Poly(dl-lactide) and Polylactide-co-glycolide in Humid Environments

The water uptake of poly(dl-lactide) (PLA) and its copolymer with glycolic acid (PLGA 50:50) has been studied using a quartz crystal microbalance (QCM). The polymers were swollen in humid atmospheres at 20 °C in order to probe both the kinetics of adsorption and the equilibrium amount of water taken up at low concentrations. The relative humidity of the air was controlled using saturated salt solutions. By equating the chemical potentials of …