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Matrix polarity effects on microphase separation in zwitterionomers, 2. Structural analysis of the model random zwitterionomers
Author(s) -
Bieglé Alain,
Mathis André,
Meurer Bernard,
Galin JeanClaude
Publication year - 2000
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 - 10.1002/1521-3935(20001101)201:17<2401::aid-macp2401>3.0.co;2-u
Subject(s) - glass transition , chemistry , crystallography , polymer chemistry , zwitterion , differential scanning calorimetry , hydrogen bond , materials science , analytical chemistry (journal) , polymer , molecule , organic chemistry , thermodynamics , physics
Matrix polarity effects on the potential microphase separation in zwitterionomers were analyzed on four homologous series of model zwitterionic A i B copolymers. They combine in their chain various A i units —CH 2 —CH(CH 2 R i )—O— of finely tuned polarity such as epichlorohydrin (PEC, R i =Cl), glycidol (PGOH, R i =OH), glycidyl acetate (PGAC, R i =O—CO—CH 3 ) or glycidyl p ‐nitrobenzoate (PGNB, R i =O—CO—C 6 H 4 —NO 2 ) and highly dipolar and constant B units —CH 2 —CH[—CH 2 —O—(CH 2 ) 2 —N + (C 2 H 5 ) 2 —(CH 2 ) 2 —O—CO—C – (CN) 2 ]—O— of the ammonioethoxydicyanoethenolate type (μ = 25.9 D, molar fraction F B < 0.3). The bulk structure of the various zwitterionomers was analyzed by differential scanning calorimetry (glass transitions) and solid state NMR ( 1 H dipolar line shape analysis, chain dynamics) and correlated with the solubility properties of a model zwitterion in a series of solvent models of the various polymeric matrices (A i ) n . a) PGOH zwitterionomers are monophasic (one T g between 3 and 31°C) as a result of specific A‐B hydrogen bonding. b) PGNB zwitterionomers are likely monophasic (one T g around 58°C) as a result of strong dipolar and dispersion A‐B interactions, but this feature cannot be definitely ascertained because of the too close glass transitions of the parent homopolymers. c) The PEC zwitterionomer of F B = 0.11 is a biphasic material characterized by a quasi‐quantitative segregation of the dipolar units in the “hard” phase (high T g ∼ 22°C) and a segregation rate of PEC units in the “soft” phase (low T g ∼ –18°C) of about 84%. d) PGAC zwitterionomers are monophasic (one T g between –12 and 15°C), despite fairly close and weak Van der Waals A‐B interactions and fairly similar matrix mobility when compared to the previous PEC case. Thus, microphase separation in model A i B random zwitterionomers appears very sensitive towards small variations of the matrix polarity and of the A‐B interactions.