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Model ω ‐Functionalized Linear Polystyrenes with One, Two, and Three Sulfobetaine End Groups: Synthesis, Characterization, and Association Behavior
Author(s) -
Sakellariou Giorgos,
Pispas Stergios,
Hadjichristidis Nikos
Publication year - 2003
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/macp.200290069
Subject(s) - polymer chemistry , chemistry , anionic addition polymerization , dynamic light scattering , end group , degree of polymerization , polymer , polymerization , molar mass distribution , osmometer , static light scattering , copolymer , size exclusion chromatography , materials science , organic chemistry , nanoparticle , nanotechnology , enzyme
Three series of ω ‐functionalized polystyrenes (PS) with different molecular weights, the first consisting of dimethylamino end‐capped PSs and the other two of ω ‐branched PSs end‐capped with two and three low‐molecular‐weight ( M n ∼ 500 g · mol −1 ) dimethylamino ω ‐functionalized polybutadienes (PB), were synthesized by high‐vacuum anionic polymerization techniques using the functional initiator ([3‐(dimethylaminopropyl)]lithium) and chlorosilane linking chemistry. The ω ‐dimethylamino polymers (precursors) were molecularly characterized by size‐exclusion chromatography, low‐angle laser light scattering (LALLS), membrane osmometry, and NMR spectroscopy. The characterization results indicate a high degree of molecular and structural homogeneity. The dimethylamino end groups were transformed to the highly polar sulfozwitterionic ones (see Figure) by reaction with cyclopropanosultone. The mono‐, di‐, and tri‐zwitterion capped polymers were found by LALLS, dynamic light scattering (DLS) and viscometry, to associate in carbon tetrachloride, a good nonpolar solvent for the PS tail. In contrast, results on dimethylamino‐capped precursors show no evidence of aggregation. Aggregation numbers increase in decalin compared with those in carbon tetrachloride. At constant molecular weight of the parental PS, the degree of association increases with increasing number of functional groups and for a given number of functional groups with decreasing molecular weight of the PS tail. Temperature‐dependent light scattering measurements in decalin indicate that aggregation persists at the highest temperature investigated.A schematic representation of the materials investigated in this study.