Oxidoreduction-Sensitive Control of Water Permeation through a Polymer Brushes-Grafted Porous Membrane

Abstract

An oxidoreduction-sensitive polymer, poly [3-carbamoyl-1-(p-vinylbenzyl)pyridinum chloride] (PCVPC), was grafted on a porous membrane, and the water permeation through the membrane was investigated. PCVPC homopolymer was found to be water soluble in the oxidized state but insoluble in the reduced state. It could be reversibly dissolved and precipitated in aqueous solutions of high ionic strengths. The polymer was grafted onto a glow-discharged fluoropolymer membrane. In the oxidized state the grafted chains were ionized and extended to cover the pores and decrease water permeation. The rate of permeation depended significantly upon the ionic strength of the aqueous solution. In the reduced state, however, the polymer brushes were deionized and increased water permeation. These changes in permeability were reversible by oxidoreduction, when the formation of an insoluble polymer complex in the reduction process was avoided under high ionic strength. The response of polymer chains grafted on the membrane corresponded to that of polymers in solution.

Preparation of hydrophilic/hydrophobic porous materials

“…Numerous research works were carried out for preparing various functional materials. Ito et al synthesized several stimuli-sensitive porous polymers, in which the permeation rate of liquid was altered responding to the change in temperature [14], PH [15], oxido-reduction [16], and photo field [17]. Choi et al grafted N -isopropylacrylamide (NIPAM) onto a porous membrane, and the obtained membrane was able to absorb hydrophobic solutes above the lower critical solution temperature (LCST) and hydrophilic solutes below the LCST [18].…”

Signal-responsive gating of porous membranes by polymer brushes

“…An oxidoreduction-sensitive polymer, poly[3-carbamoyl-1-(p-vinylbenzyl)pyridinium chloride] (PCVPC), was grafted on a porous membrane, and the water permeation through the membrane was investigated [42].…”

Smart Microfluidic Channels

“…[40,41] Modification of the inner surface of walls of microchannels with responsive thin films provides an alternative powerful means to switch interfacial energy in response to external stimuli such as temperature [42] or pH. [43][44][45] For example, responsive coatings grafted onto porous membranes were successfully used to gate liquid flow. [43,44,46,47] In this paper we extend the application of responsive coatings for the fabrication of smart microfludic channels.…”

“…[43][44][45] For example, responsive coatings grafted onto porous membranes were successfully used to gate liquid flow. [43,44,46,47] In this paper we extend the application of responsive coatings for the fabrication of smart microfludic channels. We report here on the properties, fabrication, and use of smart microfluidic channels based on responsive gradient coatings constituted of mixed polymer brushes.…”