Thermally actuated portable microvalves using elastomeric focusing

15 mins 9 secs,  57.90 MB,  iPod Video  480x270,  29.97 fps,  44100 Hz,  521.78 kbits/sec
Share this media item:
Embed this media item:


About this item
Image inherited from collection
Description: Sinha, S
Monday 13th May 2019 - 16:40 to 17:00
 
Created: 2019-05-14 13:30
Collection: The mathematical design of new materials
Publisher: Isaac Newton Institute
Copyright: Sinha, S
Language: eng (English)
Distribution: World     (downloadable)
Explicit content: No
Aspect Ratio: 16:9
Screencast: No
Bumper: UCS Default
Trailer: UCS Default
 
Abstract: Thermally actuated controlled shape changes in soft materials is a challenge as the material shows non-linear expansion characteristics. CTE of many materials is not properly available. In order to focus the expansion of the soft solid into large displacements a confined geometry is created to amplify the shape changes. Here we use an elastomer (PDMS sheet) confined between two rigid layers, which when locally heated using resistive heating expands into the micromolded channels, resulting into a massive relative displacement compared to the case of an unconfined geometry. This principle is used to make microfluidic valves which are electrically controlled (using a 3.3V-5V cellphone battery) and close in less than 100 ms. They operate within a power range of 140-160 mW generated by the specifically designed resistive heating element (in-house made ink) screen printed on the chip. We investigate the parameters of the heating element design, height dimensions and flow conditions through 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 controller for the actuating the valves.
Available Formats
Format Quality Bitrate Size
MPEG-4 Video 640x360    1.93 Mbits/sec 219.99 MB View Download
WebM 640x360    662.09 kbits/sec 73.55 MB View Download
iPod Video * 480x270    521.78 kbits/sec 57.90 MB View Download
MP3 44100 Hz 249.78 kbits/sec 27.75 MB Listen Download
Auto (Allows browser to choose a format it supports)