Self-assembly of hydrogen-bonded comb copolymer complexes of poly(p-hydroxystyrene) and 4-alkylpyridine amphiphiles

- Poly(p-hydroxystyrene) was synthesized via anionic polymerization.
- Self-assembly of hydrogen-bonded comb copolymer complexes poly(p-hydroxystyrene) with various 4-alkylpyridines was studied.
- Ordered structures are observed in which the disorder-order transition and crystallization occur quasi simultaneously.
- No liquid crystalline ordering can be observed.

The self-assembly of the hydrogen-bonded complexes between poly(p-hydroxystyrene) (PpHS) and 4-alkylpyridine amphiphiles is studied using infrared spectroscopy, differential scanning calorimetry, polarized optical microscopy, transmission electron microscopy and small- and wide-angle X-ray scattering. Interesting differences are observed with the well-studied inverted system of poly(4-vinylpyridine) and alkylphenol amphiphiles. When the alkyl tails of the 4-alkylpyridine amphiphiles are long enough, 19 and 21 respectively, an ordered lamellar structure is formed on cooling where the ordering and crystallization of the alkyl tails occur quasi simultaneously. For a shorter alkyl tail of length 17 no ordered structure is formed. This is quite different from the inverted P4VP/alkylphenol systems, where already for an alkyl tail of length 15, i.e., pentadecylphenol, an ordered structure is formed below ca. 55 °C, followed by crystallization of the alkyl tails at ca. 20 °C. This can be attributed to the possibility of (intramolecular) hydrogen bond formation of PpHS.

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