Effect of alkyl substituants structures and added ions on the phase transition of polymers and gels prepared from methyl 2-alkylamidoacrylates

Takeshi Mori, Masafumi Hamada, Toru Kobayashi, Hirokazu Okamura, Keiji Minagawa, Seizo Masuda, Masami Tanaka

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24 Citations (Scopus)


The effects of structure alteration of alkyl groups and addition of ions to solutions of new thermosensitive polymer series of poly(methyl 2-alkylamidoacrylate)s were investigated. Potential advantages of the thermosensitive polymers are their simplicity of functionalization and transition temperature control that result from their unique α,α-disubstituited structures. Poly(methyl 2-propionamidoacrylate) (PMPA) and poly(methyl 2-isobutyracrylate) (PMIBA) were thermosensitive polymers, and poly(methyl 2-acetamidoacrylate) and poly(methyl 2-n-butyramidoacrylate) were completely water-soluble and -insoluble, respectively. The PMIBA solution showed endotherm during the phase transition, while endotherm was not detected for PMPA. The difference between the two polymers resulted from the size of the hydrophobic groups. MPA gel was prepared by copolymerization with N,N'-methylenebis(acrylamide) and temperature-induced volume change of the gel was continuous. The salting-out effect of inorganic ions on PMPA solution and MPA gel followed the Hofmeister series. The inorganic (I- and SCN-) and organic ions (nPr 4N+ and nBu4N+), which showed the salting-in effect, were indicated to directly interact with PMPA chains. These ions widened the temperature range of the phase transition of the PMPA solutions. This reduced cooperativity of the phase transition was caused by size decrease of cooperative domains, which resulted from the interaction of the ions with the polymer.

Original languageEnglish
Pages (from-to)4942-4952
Number of pages11
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Issue number20
Publication statusPublished - Oct 15 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry


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