Coating Polystyrene Particles by Adsorption of Hydrophobically Modified Dextran

Surface Activity and Emulsification Properties of Hydrophobically Modified Dextrans

“…The attachment of aromatic groups on the polymeric backbone was performed as previously described (15). Typically, 10 g of dextran T40 was allowed to react with 1,2-epoxy-3-phenoxypropane in 1 M NaOH at ambient temperature for 48 h. Then, the crude products were precipitated twice with ethanol, dialyzed against deionized water for 24 h, and freeze-dried.…”

“…For dextran derivatives containing more than 11% phenoxy groups, the evolution of the reduced viscosity is no longer linear over the whole concentration range. At concentrations above 40 and 35 g/L for DexP 15 and DexP 22 solutions, respectively, the reduced viscosity deviates from a linear variation and starts to increase sharply with polymer concentration. This slope modification is due to the formation of aggregates with higher hydrodynamic volume probably because of intermolecular interactions becoming predominant at these concentrations called a Expressed with regard to the glucopyranose units.…”

“…In previous papers, we showed that the attachment of phenoxy groups on dextran led to amphiphilic derivatives (DexP), which could be securely adsorbed onto hydrophobic polystyrene surfaces through their hydrophobic sites (15). It was observed that the conformation of the adsorbed polymer and the colloidal stability of suspensions were affected by the interfacial polymer concentration and the phenoxy group content (16).…”

Surface modification of poly(lactic acid) nanospheres using hydrophobically modified dextrans as stabilizers in an o/w emulsion/evaporation technique

“…The attachment of aromatic groups on the polymeric backbone was performed as previously described. 16 Typically, 10 g of dextran T40 were allowed to react with 1,2 epoxy-3-phenoxypropane in 1M of NaOH at ambient temperature for 48 h. Then the crude products were precipitated twice with ethanol, dialyzed against deionized water for 24 h, and freeze-dried. The phenoxy content of the polymers was determined by UV spectroscopy at 269 nm, 17 and their average molecular weights (M n and M w ) were calculated from multi-angle laser light scattering (MALLS; Wyatt, Mini Dawn, Santa Barbara, California) experiments in 0.2 M of KSCN, coupled with a size-exclusion chromatography system (column Si 300 Lichrospher diol, 10 ×250 mm in diameter; Merck, Nogent/Marne, France), as already reported.…”

“…In this case, the POE segments provide the anchor to the particle shell while the hydrophilic dextran chains are protruding into the solution. 15 In previous papers, 16,17 we showed that the attachment of phenoxy groups on dextran leads to derivatives (DexP) whose amphiphilic properties clearly are evidenced by fluorescence and viscosity measurements. These derivatives adsorb onto hydrophobic polystyrene surfaces through their hydrophobic sites.…”