Rebecca L Kramer

US Patent:

20130312541, Nov 28, 2013

Filed:

Jan 24, 2012

Appl. No.:

13/981101

Inventors:

Carmel Majidi - Pittsburgh PA, US
Rebecca K. Kramer - Cambridge MA, US
Robert J. Wood - Cambridge MA, US

Assignee:

PRESIDENT AND FELLOWS OF HARVARD COLLEGE - Cambridge MA

International Classification:

G01B 7/16

US Classification:

73862454

Abstract:

A hyperelastic, soft microfluidic film measures bending curvature using a novel non-differential mechanism. Disclosed embodiments of the elastomer-based solution allows for curvature sensing directly on a bending plane and thus eliminates limitations imposed by strain gauge factor (GF) and sensor thickness (Z). Due to soft lithography microfabrication and design methods the disclosed curvature sensors are elastically soft (modulus 0.1-1 MPa) and stretchable (100-1000% strain). In contrast to existing curvature sensors that measure differential strain, embodiments of the present invention measures curvature directly and allows for arbitrary gauge factor and film thickness. Moreover, the sensor is composed entirely of soft elastomer (PDMS or Ecoflex and conductive liquid (eutectic gallium indium, (eGaIn)) and thus remains functional even when stretched to several times its natural length. Electrical resistance in the embedded eGaIn microchannel is measured as a function of bending curvature for a variety of sensor designs.