疏水缔合聚丙烯酰胺与双子表面活性剂的自组装

通过荧光光谱、动/静态激光光散射研究了疏水缔合聚丙烯酰胺(HAPAM)自组装行为及双子表面活性剂(双十四酸乙二酯双磺酸盐(DMES-14))对其的影响.实验结果表明:聚合物HAPAM在溶液中能够通过自组装形成疏水微区,表现出芘的发射光谱中第一振动峰(373nm)与第三振动峰(383nm)的荧光强度之比(I1/I3)值随聚合物浓度的增大而下降,当聚合物HAPAM浓度(CP)达到一定值后,I1/I3值不再变化;当加入表面活性剂时,HAPAM能够与双子表面活性剂在溶液中形成混合胶束,在聚合物浓度一定时,I1/I3值随表面活性剂浓度(CS)的增大急速下降,当表面活性剂浓度达到30mg·L-1时,I1/I3值趋于恒定;当表面活性剂浓度一定时,聚合物/表面活性剂二元体系中聚集体的聚集数随HAPAM浓度的增大出现先下降再增加的过程;一定量的双子表面活性剂对HAPAM分子间的缔合起促进作用,过量的双子表面活性剂对HAPAM分子间的缔合起抑制作用,使HAPAM的表观重均分子量(Mw,a)、均方根回转半径()和流体力学半径()随表面活性剂浓度增加先增大后减小,而HAPAM的/比值则随表面活性剂浓度增大出现一定程度的上升,表明HAPAM分子链段变得相对舒展.

Self-Assembly of Hydrophobically Associating Polyacrylamide and Gemini Surfactant

The self-assembly of hydrophobically associating polyacrylamide(HAPAM) and the effect of adding gemini surfactant(dimyristic acid glycol ester di(α-sodium sulfonate),DMES-14) were studied by static light scattering,dynamic light scattering,and fluorometry.HAPAM formed hydrophobic microdomains in solution through self-assembly,which decreased the fluorescence intensity ratio(I1/I3) of the first peak(373 nm) and the third peak(383 nm) in the emission spectrum of pyrene as the polymer HAPAM concentration(C P) was increased until a plateau was reached at high C P.When surfactant was added to the polymer solution,the interaction between HAPAM and surfactant resulted in the formation of mixed micelles.This caused I1 /I3 to decrease as the surfactant concentration(C S) was increased at the same polymer concentration until C S was greater than 30 mg · L-1,after which point I1 /I3 showed little change.The aggregation number of aggregates in the mixed system containing surfactant and polymer decreased at first and then increased as C P was increased.A certain amount of surfactant could enhance interchain interactions,while excess surfactant broke down interchain interactions between the hydrophobic groups of HAPAM,which resulted in maximum values of the apparent weight average molecular weight(M w,a),root-mean-square radius of gyration(),and hydrodynamic radius() of HAPAM as C S was increased./ increased slowly as C S was increased,which reflected the relative stretch of the polymer chains.