Fluorinated rheological studies

Several independent experimental methods were applied that allowed comparison of the properties of these systems [ 18-20]. We present only the principal results of the three foDowing approaches (i) rheological studies of interfacial adsorption layers (lAL) by the rotating suspension method (ii) observation of the compression of two nonpolar droplets in the surfactant aqueous solution, with measurement of the force needed for their coalescence and (iii) evaluation of the free energy of interaction between nonpolar groups of lAL and various nonpolar liquids by measuring the contact rupture force between two methylated (or fluorinated) smooth solid particles in a given liquid. 

Rheological Studies of Interfacial Adsorption Layers in Fluorinated Systems... 

Due to good optical and rheological characteristics, homopolymers of fluorine-containing methacrylates and their copolymers with other methacrylates are more often used in fibre-optic practice [2, 20-24, 26-34]. But selection of a polymer with the best optical and mechanical properties requires establishment of the dependence of the structure and properties of the polymers on the structure and reactivity of initial monomers. To solve this problem the study of the kinetics of block polymerisation and copolymerisation process of fluoroalkyl-(meth)acrylates is desirable. 

The rheological behavior of interfacial adsorption layers formed between the nonpolar phase (fluorinated or nonfluorinated) and the aqueous fluorinated or regular nonionic surfactant solution can be studied using the torsion pendulum instrument shown in Figure 4.11. The results of such studies for the adsorption layer of Pluronic F-68 formed at the interface between its aqueous solution and three different nonpolar phases are illustrated in Figure 4.31, which shows the shear stress, t, as a function of the time of deformation, t. The shear stress was applied to the entire thickness of the adsorption layer, and the time, t, was proportional to the shear deformation at a constant angular velocity, Q = 0.084 rad/s. 

W/0 gel emulsions, stabilised by hydrogenated surfactants with hydrocarbon oils, and fluorinated surfactants with fluorocarbon oils, and on OAV gel emulsions have been conducted. It is convenient to summarise their pre-paration, - macro- and microstructure,stability, " - and rheological properties - separately. Molecular modelling of such emulsions, studying the simultaneous effects of polydispersity and drop distortion on max for various packing types, has been carried out by Das et al ... 

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