Polyelectrolyte-surfactant complex films

L.W. Wang and N.F Hu, Electrochemistry and electrocatalysis with myoglobin in biomembrane-like DHP-PDDA polyelectrolyte-surfactant complex films. J. Colloid Interface Sci. 236, 166—172 (2001). 

L.W. Wang and N.F. Hu, Electrochemistry and electrocatalysis with myoglobin in biomembrane-like DHP-PDDA polyelectrolyte-surfactant complex films. J. Colloid Interface Sci. 236,166-172 (2001). Z.H. Dai, X.X. Xu, and H.X. Ju, Direct electrochemistry and electrocatalysis of myoglobin immobilized on a hexagonal mesoporous silica matrix. Anal. Biochem. 332, 23-31 (2004). 

The formation of these DNA gel particles constitutes an example of strong associative phase separation. An indication of the strength of this interaction is the formation of a stronger film (or skin) constituted by the polyelectrolyte-surfactant complex. Preliminary results of S AXS measurements have supported the existence of an ordered structure formed on the hydrated skin of the obtained particles. SEM images of the cross-section of the particles have given evidence for the existence of a shell structure, its formation being more pronounced in the case of ss-DNA. The capsule shells obtained may be considered as physical networks in which surfactant micelles form polycationic-multianionic electrostatic complexes as crosslink points. 

At relatively low polymer adsorption levels, oscillatory force profiles similar to those observed for micellar solutions are also seen in polyelectrolyte-containing systems. As with micellar structuring, these oscillations originate from an inhomogenous density distribution of polymer (or polymer/surfactant complexes) within the film. Furthermore, the characteristic length-scale of the oscillatory forces indicate that this structuring is controlled by electrostatic interactions. To date, no complete theory describing this phenomenon exists ... 

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