Synthesis and characterization of the epoxy-functionalized quaternary ammonium chloride

Studies on Intermolecular Interaction of N-Glycidyltrimethyl Ammonium Chloride Modified Chitosan/N,N-Dimethyl-N-dodecyl-N-(2,3-epoxy propyl) Ammonium Chloride and Curcumin Delivery

Chitosan has potential applications in many fields, due to its biocompatibility, biodegradability and reproducibility. However, the insolubility in water restricts its wide application. In order to expand the application of chitosan in the delivery of oil-soluble drugs and improve the efficacy of oil-soluble drugs, N-Glycidyltrimethyl ammonium chloride-modified chitosan (GTA-m-CS) and N,N-Dimethyl-N-dodecyl-N-(1,2-epoxy propyl) ammonium chloride (DDEAC), a kind of reactive surfactant, were synthesized and characterized by FTIR, NMR and XRD methods. The interactions between GTA-m-CS and DDEAC was studied by surface tension, viscosity, conductivity and fluorescence methods. The parameters, including equilibrium surface tension, critical micelle concentrations of DDEAC with different GTA-m-CS concentration, critical aggregation concentration of DDEAC, the amount of DDEAC adsorbed on GTA-m-CS, pc₂₀ and π_cmc were obtained from the surface tension curves. The influence of temperature on the above parameters were evaluated. The degree of counterion binding to micelle and the thermodynamic parameters of the system were calculated from the conductivity curves. According to the change of conductivity with temperature, the thermodynamic parameters of micellar formation were calculated. The aggregation number of DDEAC molecules in GTA-m-CS/DDEAC aggregates were calculated from steady-state fluorescence data. Based on the experimental results, the interaction models between GTA-m-CS and DDEAC were proposed. The GTA-m-CS/DDEAC aggregates could be used as curcumin carries, and achieved sustained release.

A combination of coarse-grain molecular dynamics to investigate the effects of sodium dodecyl sulfate on grafted reaction of starch-based adhesive

Graft copolymerization is a challenging step in preparation of starch-based adhesive due to the complexity and instantaneity. A combination of both experimental and simulation methodology has been employed to investigate the process at microscopic level. Through a series of characterizations of adhesives and copolymers with different SDS (sodium dodecyl sulfate) contents, 2% (w/w, 2g SDS/100 g starch) SDS demonstrated outstanding balance between the starch grafted percentage and interfacial properties. The coarse-grain molecular dynamics (CGMD) was utilized to reveal the molecular distribution and migratory mechanisms during the reaction by calculating radius distribution function (RDF) and mean square displacement (MSD). Starch chains covering the monomers surface was found to exhibit longer radius of gyration (Rg). Furthermore, the interfacial models were constructed in this study, and interfacial tension between water and VAc beads was calculated to confirm the improvement in interfacial properties and the rationality of simulation with the addition of SDS.