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2007
Book Article
Titel
Crystallization of frustrated alkyl groups in polymeric systems containing octadecylmethacrylate
Abstract
This chapter deals with the crystallization behavior of long frustrated alkyl groups as part of side chain polymers. Results from crystallization experiments on poly(n-octadecylmethacrylate) [PODMA] homopolymers with different molecular weight and on microphase-separated poly(styrene-block-octadecylmethacrylate) block copolymers [P(S-b-ODMA)] by calorimetry and scattering techniques are presented. A phenomenological picture describing the different stages of the side chain crystallization in PODMA is given. The influence of additional constraints in P(S-b-ODMA) block copolymers containing PODMA lamellae or cylinders in a glassy environment is studied. It is shown that these block copolymers are systems with a hierarchy of length scales in the nanometer range. The crystallization behavior in PODMA lamellae is basically bulk-like while strong confinement effects are indicated in case of PODMA cylinders with a diameter <20 nm by increasing crystallization times and broader transformation intervals in isothermal crystallization curves. These effects can be explained by changes concerning nucleation mechanism and crystal growth. The reduced degree of crystallinity in small cylinders is discussed based on hypothetical pictures for the internal structure of the PODMA domains.