Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (06): 1405-1410.doi: 10.3866/PKU.WHXB201203202

• SOFT MATTER • Previous Articles     Next Articles

Self-Assembly of Hydrophobically Associating Polyacrylamide and Gemini Surfactant

HAN Li-Juan1,2, YE Zhong-Bin1,2, CHEN Hong1, LUO Ping-Ya1   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, P. R. China;
    2. School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, P. R. China
  • Received:2012-01-30 Revised:2012-03-19 Published:2012-05-17
  • Contact: HAN Li-Juan
  • Supported by:

    The project was supported by the PetroChina Innovation Foundation, China (2011D-5006-0209).

Abstract: 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 (CP) was increased until a plateau was reached at high CP. 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 (CS) was increased at the same polymer concentration until CS 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 CP 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 (Mw,a), root-mean-square radius of gyration (<Rg>), and hydrodynamic radius (<Rh>) of HAPAM as CS was increased. <Rg>/<Rh> increased slowly as CS was increased, which reflected the relative stretch of the polymer chains.

Key words: Hydrophobically associating polyacrylamide, Gemini surfactant, Fluorescence spectrum, Aggregation number, Laser light scattering