Crystallization of Poly(L-lactide) in a Confined Space between Polycarbonate Layers

In this paper, various thicknesses of PLLA film between PC layers are obtained by spin coating of different amount of solution. The crystal morphologies and isothermal crystallization rates of poly(L-lactide) (PLLA) in the confined spaces between polycarbonate (PC) layers have been studied by polarized optical microscopy. The Crystal morphologies of poly(L-lactide) are little influenced by the thickness of PLLA films between PC layers. Nevertheless, the crystal growth and nucleation rates of PLLA films between PC layers are remarkably affected by the thickness of PLLA films. In the confined space, the nucleation and growth rates of PLLA films decrease as its thickness decreases. The observed phenomena has been ascribed to the reduction of molecular chain mobility, and the slow diffusion process of molecular chains. The results offer greater insights into the materials process-structure-property relationship, and help with design of future biomaterials with tailored/controlled structures/properties (such as crystallinity/ degradation rate) for specific biomedical applications.