title: Highly enhanced energy conversion from the streaming current by polymer addition.
abstract: In this contribution, we present for the first time the experimental results of energy conversion from the streaming current when a polymer is added to the working solution. We added polyacrylic acid (PAA) in concentrations of 200 ppm to 4000 ppm to a KCl solution. By introducing PAA, the input power, which is the product of volumetric flow rate and the applied pressure, reduced rapidly as compared to the case of using only a normal viscous electrolyte KCl solution. The output power at the same time remained largely constant, whereby an increase of the streaming current and a decrease of the streaming potential simultaneously occurred. These combined factors led to the massive increase of the energy conversion efficiency. Particularly, the results showed that when PAA was in a 0.01 mM KCl solution, the energy conversion efficiency of the system was enhanced by a factor of 447 (±2%), as compared to the case of the solution containing only 0.01 mM KCl. An enhancement factor of 249 (±4%) was also observed when PAA was added to the higher ionic strength background solution, 1 mM KCl. This finding can have practical use in microchannel-array energy conversion systems. When, instead of the negatively charged PAA, a non-ionic polymer polyethylene oxide (PEO) was added to the solution, no efficiency increase was observed, probably due to polymer wall adsorption.
authors.affiliation: BIOS lab on chip group, MESA+ Institution of Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Trieu
authors.initials: T
authors.lastname: Nguyen
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Xie
authors.forename: Lennart J
authors.initials: LJ
authors.lastname: de Vreede
authors.forename: Albert
authors.initials: A
authors.lastname: van den Berg
authors.forename: Jan C T
authors.initials: JC
authors.lastname: Eijkel
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004553:Electric Conductivity; D011211:Electric Power Supplies; D011189:Potassium Chloride / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C006903:carbopol 940; D011189:Potassium Chloride