Molecularly imprinted solid-phase extraction sorbent for removal of nicotine from tobacco smoke

A sorbent showing specific affinity for nicotine was prepared by molecular imprinting technique, using nicotine as the template, methacrylic acid (MAA) as the functional monomer, ethyleneglycol dimethacrylate (EDMA) as the crosslinker and chloroform as the porogen. UV spectroscopic analysis in the molecular imprinting prepolymerization stage confirmed that nicotine could complex with the functional monomer by electrostatic interaction (ionic interaction and hydrogen bonding). The affinity and the binding properties of the imprinted polymer towards nicotine were investigated by equilibrium rebinding experiments. The results indicated the presence of nicotine-specific binding sites in the imprinted polymer, and that the imprinted polymer had a good capacity (90 mumol/g polymer) for nicotine. The elution conditions were optimized on the column packed with the imprinted polymer to elute nicotine quantitatively. The imprinted polymer was used as a solid-phase extraction (SPE) material for the removal of nicotine from tobacco smoke. The results obtained showed that the imprinted polymer was superior in terms of removing nicotine in tobacco smoke, compared with the commercial filter tip.

Pore-filling membrane for direct methanol fuel cells based on sulfonated poly(styrene-ran-ethylene) and porous polyimide matrix

We have synthesized a porous co-polyimide film by coagulating a polyimide precursor in the non-solvent and thermal imidization. Factors affecting the morphology, pore size, porosity, and mechanical strength of the film were discussed. The porous polyimide matrix consists of a porous top layer and a spongy sub-structure with micropores. It is used as a porous matrix to construct sulfonated poly(styrene-ran-ethylene) (SPSE) infiltrated composite membrane for direct methanol fuel cell (DMFC) application. Due to the complete inertness to methanol and the very high mechanical strength of the polyimide matrix, the swelling of the composite membrane is greatly suppressed and the methanol crossover is also significantly reduced, while high proton conductivity is still maintained. Because of its higher proton conductivity and less methanol permeability, single fuel cell performance test demonstrated that this composite membrane outperformed Nafion membrane.