Synthesis of crosslinked polyurethane and Network constrained surface phase separation

To create functional surfaces for soft materials, such as polyurethanes, our approach is to use a semifluorinated surface modifier as minor component to the matrix material. The surface modifier, driving by reduction in surface energy, surface-concentrates to form a functionalized surface layer at the air-polymer interface. In our previous studies, linear PTMO-based polyurethanes were used as the matrix material. These systems undergo slow surface phase separation at room temperature due to the thermodynamically immiscibility of the soft blocks. In this study, chemically crosslinked matrix was developed to provides a steric hindrance to constrain the mobility of surface modifier and to form a kinetically stable surface. The physical property and morphology of base crosslinked matrix has been characterized using DSC, UTT, DMA and AFM. The surface morphology of surface modified crosslinked matrix has been characterized using AFM, DCA and XPS