(201h) The Effect of Microenvironment on the Catalytic Ability of Multifunctional Nanoreactors
Multifunctional nanoreactors that combine reaction and separation can lead to more efficient reactions and reduce hazardous waste. We propose to use multifunctional polymer nanoreactors for liquid phase oxidation reactions and product isolation by spontaneous phase separation. Currently, the effect of the polymer microenvironment on reaction kinetics are being studied using the reduction of 4-nitrophenol. Nanoreactors encapsulating catalytic gold nanoparticles were self-assembled using confined impinging jet mixers. The self-assembly was directed by micellization of an amphiphilic block copolymer, polystyrene-b-polyethylene glycol. Adsorption of the hydrophobic block encapsulates the catalyst while the other block sterically stabilizes the nanoreactor. The characteristics of the polymer microenvironment wasvaried by including polystyrene, vitamin E, and dodecane as co-precipitants. The reduction of 4-nitrophenol is tracked using UV-Vis spectroscopy as a function of reaction time. Nanoreactors with polystyrene cores show longer induction times than Vitamin E cores and can be attributed to a slower reagent diffusion rate. However, the polystyrene core nanoreactors demonstrate faster apparent reaction rates than the Vitamin E. With a dodecane core, no catalytic reduction is observed potentially due to the low solubility of the reactants. Quantifying the effect of core material on reagent diffusion and apparent catalyst reactivity is currently being investigated.