ULTRATHIN CROSS-LINKED MEMBRANES AT THE INTERFACE BETWEEN OIL AND WATER

The tensio-active properties of different types of diesters can be use d to synthesize two-dimensional model networks at the interface betwee n oil and water. We have systematically studied rubber-elastic, glass- like and transient membranes, which are stabilized and crosslinked by physical or chemical contacts. The kinetics of surface gelation and th e mechanical properties of the crosslinked membranes were investigated by measuring two-dimensional theological parameters, such as the shea r modulus or the surface viscosity. The experimental data of these inv estigations are in fairly good agreement with the theoretical predicti ons of percolation theories. Further informations on the molecular str ucture of the crosslinked membranes can be obtained from electron spin resonance (ESR) measurements. Using spin labels of significantly diff erent sizes, which are diffusing from the aqueous environment into the oil phase, it is possible to determine the average mesh size of the i nterfacial network structure. The systematic study of these ultrathin membranes offers new insights into aspects of current research, and op ens interesting new technical applications.