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Nonionic gemini surfactants HBA(EO)80 were synthesized and characterized by means of surface tension measurements. CMCs of two mixed system, nonionic gemini mixed with anionic gemini (HBA(EO)80/C11pPHCNa) and nonionic gemini mixed with anionic monomeric (HBA(EO)80/SL) and the effect of salt on the two mixed system were investigated. Freeze-fracture transmission electron microscopy and scanning electron microscopy were used to investigate the mixed aggregates' morphologies. The results show that large spherical aggregates were formed in the mixed solution, which trend to transfer into micelles with the increases of the salt concentration. [ABSTRACT FROM AUTHOR]

Rheologic properties and the conformations of the mixed system of hydrophobically modified polyacrylamide and surfactants in distilled water with or without NaCl were investigated. The vacuum sublimation freezing-drying technique was employed to maintain the aggregation state of the mixed systems. Scan electron microscopy and transmission electron microscopy were used to investigate microstructure of the mixed systems formed, and obtain the system molecular configuration information. The results showed that the rheologic behavior of the mixed solution revealed by viscosity data and microconformation obtained depend on the salt existence and the hydrophobic group content of the polymer. The relationship between polymer microconformation and the macroscopic properties for the mixed systems was analyzed to explore the aggregating mechanism. [ABSTRACT FROM AUTHOR]

With the vacuum sublimation freezing-drying and rheological techniques, the salt/alkali/surfactant effects on the solution properties and the aggregate conformations of the polymers, synthesized hydrophobically modified poly (acrylamide) (HMPAM), were investigated. The experimental methods included viscosity measurements, the photomicroscopy, scan electron microscopy, and the freeze fracture transmission electron microscopy. The variety of conformations of the ultramolecular aggregates, the hydrophobical region, and the spatial network structures resulted from the hydrophobical interaction were studied. Combined results confirmed that HMPAM could form several of interesting three-dimensional network structures either in distilled water or NaCl solution. The results have revealed the mechanism of the salt/alkali/surfactant effects on the peculiar rheological properties of the solution. [ABSTRACT FROM AUTHOR]