Premium
Mesophase structures of solid poly( N ‐alkylacrylamides) as revealed by SAXS
Author(s) -
Antonietti Markus,
Burger Christian,
Micha Marc André,
Weissenberger Markus
Publication year - 1999
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19990101)200:1<150::aid-macp150>3.0.co;2-#
Subject(s) - small angle x ray scattering , mesophase , polymer chemistry , polymer science , materials science , chemistry , organic chemistry , scattering , physics , phase (matter) , optics
Small angle X‐ray scattering (SAXS) on films of poly( N ‐alkylacrylamides) with various chain lengths reveals that these well known polymers exhibit a microphase‐separated solid‐state structure with liquid crystalline order. Analysis of the phase morphology in dependence on the alkyl side chain length results in the following scenario: For the C 8 and C 10 tail, the microphases are just weakly developed and quantitative analysis of the broad scattering peak reveals an ill‐defined structure without sharp phase boundaries. For the C 12 and C 14 derivative, we found a well developed mesophase, which shows a number of scattering peaks and cannot be related to any classical phase morphology. For these two materials, a phase model is developed on the base of a new technique of quantitative evaluation of the X‐ray data. Poly( N ‐hexadecylacrylamide) and poly( N ‐octadecylacrylamide) exhibit lamellar morphologies with low long range order. Poly( N ‐octadecylacrylamide) obtained by polymerization instead of polymer reaction exhibits a different phase morphology which resembles the so‐called sponge‐like phase. The different phase morphologies are also reflected in the thermal behavior where the sponge phase shows a lower melting point and melting enthalpy of the side chains than the lamellar mesophases, regardless of the longer alkyl chains involved in this system.