疏水改性丙烯酰胺共聚物在水溶液中的缔合

罗丹明B荧光探针发现丙烯酰胺(AM)/丁基苯乙烯(BST)/2-甲基-2-丙烯酰胺基丙磺酸钠(NaAMPS)共聚物(PASA)在0.05 g/dL水溶液中疏水微区的黏度已较大,说明PASA具有强的疏水缔合效应。动态光散射结果表明,PASA在0.005 g/dL极稀溶液中,主要以单分子存在,部分单分子链发生了分子内缔合;在0.01 g/dL~0.2 g/dL范围内,溶液中均有构象伸展和卷曲的单分子存在,粒径有单分子区和疏水缔合区;当共聚物浓度增加为0.3 g/dL时,流体力学半径分布为单分散,只有缔合体存在。随着分子中疏水链段含量的增加,0.1 g/dL PASA溶液的疏水缔合体(Rh:2800 nm~5000 nm)的数量增加,溶液黏度显著升高。

Association of Hydrophobically Acrylamide-Modified Copolymer in Aqueous Solution

The viscosity measurement of the poly(acrylamide/butylstyrene/sodium 2-acrylamido-2-methylpropane sulphonate)(PASA) in microenvironment using rhodamin B as the fluorescent probe shows that the microviscosity of 0.05 g/dL PASA solution is very high,indicating strong intermolecular association of hydrophobic groups.The studies of dynamic light scattering show that the polymer molecules mainly exist in the form of mono-molecule and intramolecular associations occuring in the 0.005 g/dL PASA aqueous solution.In 0.01 g/dL~0.2 g/dL PASA aqueous solution,the hydrodynamic radius(Rh) distribution consists of two regions: expanding and coiled mono-molecules,and hydrophobic associating molecules.The distribution of Rh in 0.3 g/dL PASA aqueous solution is mono-disperse,and only aggregates exist.With increasing hydrophobic monomer content in the polymer molecules,the number of aggregates with Rh of 2800 nm~5000 nm increases in 0.1 g/dL PASA aqueous solution,resulting in the remarkable increase in the apparent viscosity of PASA aqueous solution.