Role of long-chain backbone in side-chain crystallization of densely grafted comb-like polymers

Crystallization behaviors of alkane side-chains in densely grafted comb-like vinyl or acrylate polymers are influenced by their long-chain backbones as observed in experiments. By means of dynamic Monte Carlo simulations of the lattice polymer model, we compared cooling and isothermal crystallization behaviors of side chains in bulk alternatingly grafted polymers separately holding crystallizable and non-crystallizable long-chain backbones. The results of a series of side-chain lengths showed that both non-crystallizable backbones and very short side chains suppress side-chain crystallization in agreement with experiments, demonstrating the constraint effects of the backbone on side-chain crystallization. However, both crystallizable and non-crystallizable long-chain backbones maintain their nearly random-coil conformation over side-chain crystallization, not adopting the expected bottle-brush shapes. We discussed the related experimental observations on crystal morphologies that derived the bottle-brush assumption. Our observations facilitate a better understanding of structure-property relationships for side-chain crystallization in densely grafted comb-like polymers holding relatively long backbones.