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Hydrophobically modified acrylamide‐based polybetaines. I. Synthesis, characterization, and stimuli‐responsive solution behavior
Author(s) -
Johnson Kathryn M.,
Fevola Michael J.,
McCormick Charles L.
Publication year - 2004
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.13646
Subject(s) - monomer , polymer , betaine , polymer chemistry , polyelectrolyte , comonomer , copolymer , aqueous solution , chemistry , hydrodynamic radius , acrylamide , methacrylamide , potentiometric titration , virial coefficient , chemical engineering , organic chemistry , ion , physics , quantum mechanics , engineering
Acrylamide‐based, hydrophobically modified (HM) polybetaines containing N ‐butylphenylacrylamide (BPAM) and varying amounts of the sulfobetaine monomer 3‐(2‐acrylamido‐2‐methylpropanedimethylammonio)‐1‐propanesulfonate (AMPDAPS) or the carboxybetaine monomer 4‐(2‐acrylamido‐2‐methylpropyldimethylammonio)butanoate (AMPDAB) were synthesized by micellar copolymerization. The corresponding control (co)polymers lacking BPAM or betaine comonomers were also prepared. The terpolymers were characterized by 13 C‐NMR and UV spectroscopy, classical light scattering, and potentiometric titration. Low charge density polymers contained 3.9–8.6 mol % betaine, whereas the high charge density systems contained 17–25 mol % betaine; the HM polymers contained up to 1.0 mol % BPAM as the hydrophobe. The weight‐average molecular weights of the polymers ranged from 4.19 × 10 5 to 1.29 × 10 6 g/mol, and most HM polymers exhibited negative second virial coefficients. The p K a of the carboxybetaine moieties was found to increase with increasing levels of hydrophobic and betaine comonomer incorporation. The response of aqueous polymer solutions to various external stimuli, including changes in solution pH and electrolyte concentration, was investigated using rheological analysis. The solution behavior of the polymers was characteristic of HM polyacrylamides and acrylamide‐based polyzwitterions. The high charge density HM polycarboxybetaine exhibited unusual solution behavior that can be explained in terms of electrostatic, hydrophobic, and hydrogen‐bonding associations. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 647–657, 2004