The role of water in modulating reactivity within selectively permeable membranes.

PHYS 330

John Walker, john.e.walker1@us.army.mil1, Heidi Schreuder Gibson, heidi.schreudergibson@us.army.mil1, Phillip Gibson2, and Jan W. Andzelm, jandzelm@arl.army.mil3. (1) US Army Natick Soldier Research, Development, & Engineering Center, Natick Soldier Center, 15 Kansas Street, Natick, MA 01760, (2) U.S. Army Natick Soldier Research, Development and Engineering Center, 15 Kansas Street, Natick, MA 01760, (3) Multifunctional Materials Branch, US Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Ground, MD 21005-5069
A co-polymer of poly(vinyl alcohol) and poly(vinylamine)-M12 [ERKOL] obtained from Celanese, has been demonstrated to be an effective decon material for G-agents both as a powder and as a film. Dynamic moisture permeation tests showed that cast membranes of the M12 co-polymer exhibit high permeability to water vapor. Variable barrier properties towards chloroethyl ethyl sulfide (half-mustard) have been measured on films conditioned at different humidities of 0, 50, and 80rh, corresponding to film water activities (Aw)of 0,0.5, and 0.8. Studies on the effect of moisture on the reactivity of ERKOL M12 to hydrolyze the G-agent analogue diisopropyl fluorophoshate (DFP) revealed that below an Aw of 0.88, no hydrolysis of DFP took place. In this paper we report on the molecular modeling of the M12 membrane in the presence of water at levels above 88% rh (Aw=0.88) emplying molecular dynamics and Steered Molecular Dynamics (to probe events on timeframes not accessible through standard dynamics simulations).
 

PHYS Poster Session - Water Mediated Interactions
7:30 PM-10:00 PM, Wednesday, August 20, 2008 Pennsylvania Convention Center -- Hall C, Poster

Division of Physical Chemistry

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008