DODAC vesicles

NaA0T-n-heptane-H20 reversed micelles Single-compartment, 800-to 1000-A-diameter dihexadecylphosphate (DHP) surfactant vesicles Single-compartment dioctadecyldimethylammonium chloride (DODAC) (6) vesicles Thiophenolate-ion-capped, size-quantized CdS generated in situ in reversed micelles CdS particles prepared in situ in vesicles from Cd2+ by controlled exposure to h2s CdS particles generated in situ in DODAC vesicles by several methods... 

Single-bilayer dioctadecyldimethylammonium chloride (DODAC) (6) vesicles Sonication of surfactant-stabilized magnetite with DODAC Vesicle-incorporated magnetite influenced the outcome of benzophenone photolysis 789... 

In an attempt to overcome the problem of accumulation of the oxidized electron donor, we have incorporated a recyclable surface-active electron donor in DODAC vesicles (12). This electron donor contains a sulfide moiety which dimerizes upon light-induced oxidation. Simultaneously, hydrogen is evolved via vesicle-stabilized, catalyst-coated, colloidal CdS particles. The dimer could be chemically reduced for additional hydrogen formation. Figure 9 is an idealized view of this cyclic process (12). 

Figure 9. An idealized model for the cyclic oxidation-reduction process using thiol-functionalized surfactant, incorporated into DODAC vesicles together with Rh-coated colloidal CdS, for sustained hydrogen generation under visible light irradiation in one part of the cycle.

Influence of Field Effect. Since electron transfer rates are directly related to the field, a judicious manipulation of the distance of a sensitizer and an electron acceptor (or donor) from a highly charged surface across the Stem layer (Figure 2, equation 7) is expected to result in altered efficiencies. This expectation has been realized In achieving effective charge separation under the Influence of a positive electric field, generated by DODAC vesicles (35). Rate constant for electron transfer from L-cystelne to the excited state of Ru(bpy) ... 

Vesicles of dioctadecyldimethylammonium chloride (DODAC) are relatively resistant to permeation of organic anions at 25 °C, at imposed exolendo pH gradients of 3 units. Thiophenolate anions, for example, can not be oxidized by o-iodosobenzoate if both reagents are encapsulated in DODAC vesicles (Figure 4.20). Reaction occurs immediately after addition of some ethanol. 

Incorporation of monomers with similar characteristics to the hydrophobic tails of the surfactants involved (typically alkane chains of DODAB and DMPC) tends to suppress phase separation somewhat, and results in either multi-polymer bead aggregates (e.g., necklaces) or parachutes containing an elliptical rather than a spherical latex bead. Copolymerization of butyl methacrylate with ethylene glycol dimethacrylate in DODAB vesicles resulted in polymer necklaces where the polymer beads appear randomly dispersed in the vesicle bilayer [15] in contrast to the polymer shells observed by Hotz and Meier [10] for the same reaction in DODAC vesicles. Similarly, polymerization of octadecylacry-late, another straight-chain monomer, in DODAB vesicles produced parachutes with extremely elHpsoidal polymer beads in contrast to the rather spherical beads observed commonly for the polymerization of aromatic monomers such as styrene in DODAB [12]. Presumably these differences are caused by an increased compatibility between the surfactant bilayer and the monomer chosen. 

All substrates tested were epoxidized with good turnover numbers. On the contrary, in DODAC vesicles, no epoxidation took place. The reason may be that the micro-enviroment of the latter vesicles is too reductive, or that the concentration of protons, required for epoxidation is too low at the positively charged interface. Further experiments are required to substantiate this. 

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