SM01.11.05 : Directional Transportation of Non-Polar Molecules in Organogel Films

4:30 PM–4:45 PM Apr 5, 2018 (America - Denver)

PCC West, 100 Level, Room 104 AB

Mohammad Ali1 Tsung-Han Tsai1 Paul Braun1

1, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States

Materials which selectively drive molecule offer unprecedent opportunities for separation and concentration of molecules. In recent years, approaches utilizing molecular motors and chemical potential gradient to drive molecular transport were well discussed in the literatures. However, directional transportation of non-polar molecule is yet to explore. We will present two different methods to transport non-polar molecule in organogel films. In the first method, we utilize a travelling chemical wave generated by an ion exchange process (which converts the gel from hydrophobic to hydrophilic) to drive the transport of non-polar molecules entrained within a quaternary ammonium-based organogel film. The hydrophilic region expands with a sharp transition at the leading edge. The sharpness of the chemical potential gradient at the leading edge of the propagating chemical wave provides a strong driving force for analyte transport. The leading edge moved up to 500 μm within 30 min, while the gradient length (the distance from the start to the end of the gradient region) remained 20 μm or less over this time. In another method, nerve agent is directionally transported via chemical gradient built-in organogel. Since phosphoryl (P=O) group on the organophosphorus structure is H-bond acceptor, therefore we aim to fabricate hydroxyl (-OH) group gradient in the gel to drive organophosphorus molecule directionally. Pentafluorophenyl acrylate (PFPA) based polymeric active esters was selected as the molecular transport media. The reactivity of pentafluorophenyl group towards primary amine allows us to manipulate desired functionalities via reaction with amine-appended molecules. A 70-fold concentration of aerosol dosed nerve agent simulant, dimethyl methylphosphonate at the center of a radially symmetric gradient was observed. This concept of gradient-directed molecular transport should enable the autonomous processing of a diversity of chemical species in organic media.