Hydrogels from Surfactant Solutions

The structure of the microdomains which form in surfactant solutions is shown schematically in Fig. 5.1. Side chains and surfactant molecules combine to form aggregates resembling mixed micelles dispersed throughout the bulk aqueous network. The composition of these microdomains has been investigated using a fluorescence probe technique adapted from the surfactant literature [2]. Results are summarized in Table 5.1 and Fig. 5.2. The total aggregation number, Nj, of the clusters is equal to the sum of the number of surfactant molecules and alkyl side chains N and respectively) in each 

The structure of the networks formed in these systems is profoundly affected by the composition of the microdomains. As more side chains become incorporated into each aggregate, the length of the polymer segments between aggregates goes down, and the storage modulus of the network increases, as shown in Fig. 5.3 [2]. 

The 13/11 values for HMHEC gels are significantly higher than those of the corresponding solvents or of any of the control solutions (Fig. 5.4). Thus it is clear that there are distinct hydrophobic regions in the gels which are not 

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Two approaches have been used successfully in producing dispersed phase hydrogels from surface-active graft copolymers. In one approach, the polymer, which is insoluble in water due to its high alkyl side chain content, is solubilized in ethanol/water solutions, permitting the side chains to come into close contact and form hydrophobic microphases spontaneously. In the second approach, we have used surfactant at... 

Trehalose tetraesters characterised by ID and 2D H and C NMR and ESI-MS as biosurfactants (rather than cryoprotectants) were isolated from a soil strain of Micrococcus luteus. Solubilisation of phenol within mieellar aggregates of hexadecyltrimethylammonium bromide (HTAB) in aqueous solutions were investigated by H NMR in D20. The synthesis and properties of non-cytotoxic carboxymethylcellulose-chitosan hydrogels modified with poly(ester-urethane) was reported. 2D NOE NMR gave new insights into the interactions between polyamidoamine dendrimers and different surfactants including SDS and dodecyltrimethylammonium bromide. The ability of a- and (3-CDs to disrupt a surfactant mixed micelle of an equimolar mixture of octyltriethylammonium bromide (OTEAB) and sodium perfluorooctanoate (SPFO) was studied by H and F NMR. The effect of ethanol on the micellization of SDS (anionic... 

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