title: Thermoactuated diffusion control in soft matter nanofluidic devices.
abstract: The diffusive transport rate in a soft matter nanofluidic device is controlled with a thermoactuated hydrogel valve. The device consists of three giant unilamellar vesicles linearly conjugated by lipid nanotubes, with a solution of the stimuli-responsive polymer poly(N-isopropyl acrylamide) (PNIPAAm) in the central vesicle. The valve states "high (transport) rate" and "low (transport) rate" are obtained by heat-activated switching between PNIPAAm's dissolved and compact aggregated states. We show that three parameters influence the diffusion rate within the device: the increase of the transport rate caused by a decrease in PNIPAAm concentration upon compaction, the temperature dependence of the buffer viscosity, and the volume excluded by the PNIPAAm hydrogel compartment.
authors.affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-41296 Göteborg, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Markström
authors.forename: Ludvig
authors.initials: L
authors.lastname: Lizana
authors.forename: Owe
authors.initials: O
authors.lastname: Orwar
authors.forename: Aldo
authors.initials: A
authors.lastname: Jesorka