Autonomic molecular transport by polymer films containing programmed chemical potential gradients

Chunjie Zhang, Amit Sitt, Hyung Jun Koo, Kristopher V. Waynant, Henry Hess, Brian D. Pate, Paul V. Braun

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)5066-5073
Number of pages8
JournalJournal of the American Chemical Society
Issue number15
StatePublished - 22 Apr 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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