LUMINESCENCE STUDIES OF HYDROPHOBICALLY-MODIFIED, WATER-SOLUBLE POLYMERS .1. FLUORESCENCE ANISOTROPY AND SPECTROSCOPIC INVESTIGATIONS OF THE CONFORMATIONAL BEHAVIOR OF COPOLYMERS OF ACRYLIC-ACID AND STYRENE ORMETHYL-METHACRYLATE
Jr. Ebdon et al., LUMINESCENCE STUDIES OF HYDROPHOBICALLY-MODIFIED, WATER-SOLUBLE POLYMERS .1. FLUORESCENCE ANISOTROPY AND SPECTROSCOPIC INVESTIGATIONS OF THE CONFORMATIONAL BEHAVIOR OF COPOLYMERS OF ACRYLIC-ACID AND STYRENE ORMETHYL-METHACRYLATE, Canadian journal of chemistry, 73(11), 1995, pp. 1982-1994
Fluorescence spectroscopy and anisotropy measurements have been used t
o study a series of styrene - acrylic acid, STY-AA, and methyl methacr
ylate - acrylic acid, MMA-AA, copolymers in dilute methanolic and aque
ous solutions. Copolymerization of either STY or MMA with AA has littl
e effect upon the rate of intramolecular segmental motion in methanol
solutions. In aqueous media, intramolecular hydrophobic aggregation oc
curs and restricts the macromolecular dynamics to an extent dependent
upon pH, nature of the comonomer, and copolymer composition. The hydro
phobic domains formed in these copolymer systems can solubilize organi
c guests. In this respect, STY is a more powerful modifier of AA-based
polymer behaviours than is MMA. In general, the hydrophobic modificat
ion increases the solubilization power of the resultant polymer. Furth
ermore, the copolymers retain their solubilization capacities to highe
r values of pH the more hydrophobic the comonomer and the greater its
content in the copolymer. The interiors of the hydrophobic aggregates
reduce the mobilities of occluded guests: the microviscosities of the
domain interiors depend upon the nature of the hydrophobe, pH, and cop
olymer composition.