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SUMMARY:Thermally actuated portable microvalves using elastomeric focusing
  - Shayandev Sinha (Harvard University)
DTSTART:20190513T154000Z
DTEND:20190513T160000Z
UID:TALK124297@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Thermally   actuated controlled shape changes in soft material
 s is a challenge as the   material shows non-linear expansion characterist
 ics. CTE of many materials is   not properly available. In order to focus 
 the expansion of the soft solid   into large displacements a confined geom
 etry is created to amplify the shape   changes. Here we use an elastomer (
 PDMS sheet) confined between two rigid   layers\, which when locally heate
 d using resistive heating expands into the   micromolded channels\, result
 ing into a massive relative displacement compared   to the case of an unco
 nfined geometry. This principle is used to make   microfluidic valves whic
 h are electrically controlled (using a 3.3V-5V   cellphone battery) and cl
 ose in less than 100 ms. They operate within a power   range of 140-160 mW
  generated by the specifically designed resistive heating   element (in-ho
 use made ink) screen printed on the chip. We investigate the   parameters 
 of the heating element design\, height dimensions and flow   conditions th
 rough the valves. This technique helps us to make multiple   valves along 
 the fluidic pathway with arbitrary positioning. The size of   these really
  help to make the devices portable as one does not need a   separate contr
 oller for the actuating the valves.
LOCATION:Seminar Room 1\, Newton Institute
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