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We study new methods for the elaboration of nanoporous biomaterials intended to deliver encapsulated molecules via diffusion. The strategy consists of casting a polylactide biopolymer around templating micelles strictly using soft preparation methods. The micelles are polyion complex micelles prepared from double hydrophilic block copolymers and hydrosoluble polyamines in aqueous solution. We show...
The interactions of the cationic cellulose ether derivatives JR400 and LM200 with cationic surfactants differing in both the alkyl chain length and head group composition were investigated using microcalorimetric techniques. The presence of polymer-induced surfactant aggregation and polymerbound aggregates was detected for the majority of the surfactants investigated. The thermodynamic properties...
The micellization dynamics of Pluronic L64 in aqueous NaCl solutions was investigated by employing the stopped-flow (SF) technique. With salt-jump experiments (i.e. fast increase of NaCl concentration) it was possible to study the aggregation dynamics for solutions that initially contained only unimers, since the addition of NaCl induces micellization. Using the capability of SF to observe reversible...
Homopolymer steric stabilization of aqueous mineral particle suspensions is generally brought about by adsorption and formation of a polymer layer at the solid-liquid interface. Hence, with homopolymers arise the problems of efficient adsorption on the solid surface and also satisfactory compatibility or dispersibility of the polymer in the liquid. These problems may be solved by using diblock copolymers,...
This paper reports titration microcalorimetric measurements on micellization of a technical grade alkyl polyglucoside (APG) surfactant. The dilution enthalpy was recorded at three different temperatures and the curves obtained were compared to those of pure β-octyl glucoside. For comparative purposes titration microcalorimetry was also conducted with the conventional nonionic surfactant octa (ethylene...
The binary phase diagram of the hexadecyltrimethylammonium sulphate-water system has been determined by 2H NMR and polarized microscopy methods. At 295 K, the phase diagram comprises a large isotropic solution region (up to 40.5 % surfactant) and isotropic cubic, I1, (41–46.5 °/o) and anisotropic hexagonal, E, (51–60 °/o) liquid crystalline phases. On increasing the temperature, the I1 phase dissappears...
The energetics of the process of micellization of zwitterionic surfactants in aqueous solutions and their adsorption onto silica gel has been investigated. Differential molar enthalpies of dilution and adsorption were measured for (dodecyldimethylammonio) ethanoate, (dodecyldimethylammonio) butanoate, and 3-dodecyldimethylammonio)-1-propanesulfonate in pure water or in 0.1 M NaCl solution and at 298...
Results of stochastic simulations of micellization kinetics are presented. The algorithm used was derived from the general Monte Carlo method introduced by D.T. Gillespie (1976, J. Phys. Chem. 22:403–434) and applied to micelle formation according to a mechanism that allows association and dissociation among n-mers of whatever aggregation number. With a careful choice of thermodynamic and dissociation...
The report is concerned with the functioning of ion-selective electrodes responding to surface-active agents in solutions of aggregated surfactants. Contrary to the current mechanisms destined for inorganic sensors, it has been suggested that adsorbed species and surface aggregates (hemimicelles and admicelles) on the membrane surface are essential factors in the response and functioning of surfactant...
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