1. Autonomic molecular transport by polymer films containing programmed chemical potential gradients
- Author
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Amit Sitt, Chunjie Zhang, Paul V. Braun, Hyung-Jun Koo, Henry Hess, Kristopher V. Waynant, and Brian D. Pate
- Subjects
Tertiary amine ,Diffusion ,Kinetics ,Analytical chemistry ,Acrylic Resins ,Chemical Fractionation ,Biochemistry ,Catalysis ,Hydrogel, Polyethylene Glycol Dimethacrylate ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Molecule ,Particle Size ,chemistry.chemical_classification ,Molecular Structure ,Hydrolysis ,Cationic polymerization ,Substrate (chemistry) ,General Chemistry ,Polymer ,Boronic Acids ,chemistry ,Chemical physics ,Boronic acid - Abstract
Materials which induce molecular motion without external input offer unique opportunities for spatial manipulation of molecules. Here, we present the use of polyacrylamide hydrogel films containing built-in chemical gradients (enthalpic gradients) to direct molecular transport. Using a cationic tertiary amine gradient, anionic molecules were directionally transported up to several millimeters. A 40-fold concentration of anionic molecules dosed in aerosol form on a substrate to a small region at the center of a radially symmetric cationic gradient was observed. The separation of mixtures of charged dye molecules was demonstrated using a boronic acid-to-cationic gradient where one molecule was attracted to the boronic acid end of the gradient, and the other to the cationic end of the gradient. Theoretical and computational analysis provides a quantitative description of such anisotropic molecular transport, and reveals that the gradient-imposed drift velocity is in the range of hundreds of nanometers per second, comparable to the transport velocities of biomolecular motors. This general concept of enthalpy gradient-directed molecular transport should enable the autonomous processing of a diversity of chemical species.
- Published
- 2015