The design and implementation of a controlled macromolecular chemical transport system could greatly advance switchable chemical reactions and be applicable for targeted drug delivery, intelligent inks, and nanotechnology. To better understand the mechanisms of function for a switchable macromolecular transport system, preliminary work has been completed that studies the transport of bromothymol blue (BB) facilitated by cetylpyridinium bromide hydrate (CPBM) to a silica surface that has been modified with Poly(styrene-co-maleic anhydride), a pH switchable polymer. Ultraviolet spectroscopic trials were conducted measuring the absorbance of BB and CPBM at two pH levels, while holding BB at a constant 1x10-5 M, varying CPBM between 1 and 10x10-5 M. Under acidic conditions at pH 3.5, BB and CPBM were attracted to the silica surface, however CPBM had a lower surface concentration, varying from 0.7 to 1.7 times lower. Additionally as the concentration of CPBM was increased, the time to surface of the BB and CPBM also increased by doubling in time at an 8 fold concentration increase. Under basic conditions at pH 9.5, initial attraction of the BB was observed to the silica surface above a concentration of 3x10-5 M however; as CPBM concentration increased at the surface, the BB concentration decreased. A concentration of 4.5x10-5 M of CPBM was needed before a low concentration of BB would remain on the silica surface. The difference in attraction under both acidic and basic conditions was due to columbic repulsion between the negatively charged BB and the negatively charged surface. The surface coverage of the bound polymer also was noted to play a role in attraction of the BB and CPBM, with a lower surface coverage having a greater attraction of BB and CPBM. Further work is to be completed by investigating the reversibility of BBs attraction/repulsion to the silica surface using polyelectrolytes as vehicles of removal as well as further work done on the effect of surface coverage of the bound polymer on the silica surface.

Studies on the mechanisms of forced transport of dye through solution modifications to a polymerized surface

249th National Meeting (2015)

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