On the crystallization behavior of frustrated alkyl groups in poly(n-octadecyl methacrylate)

The side chain crystallization of poly(n-octadecyl methacrylate) (PODMA) homopolymers with different molecular weight as well as small lamellar and cylindrical PODMA domains in microphase-separated poly(styrene-b-octadecyl methacrylate) block copolymers is studied by calorimetry and scattering techniques. Based on the results of these experiments and the knowledge about the properties of lower amorphous poly(n-alkyl methacrylates) a picture for the crystallization process in PODMA and the transition of the frustrated alkyl groups from the amorphous to the crystalline state is proposed. Details of the situation in the preordered melt, during nucleation and early stages of crystallization as well as primary and secondary crystallization are discussed. The influence of immobile main chains on the crystallization of long alkyl groups is considered and the situation is compared to that in other systems containing long alkyl sequences like alkanes or polyethylene.