US 12,216,010 B2
Flexible devices incorporating electronically-conductive layers, including flexible wireless LC sensors
Philip James Walton Hands, Edinburgh (GB); Vasileios Mitrakos, Edinburgh (GB); Lisa Miriam MacIntyre, Edinburgh (GB); and Marc Philippe Yves Desmulliez, Edinburgh (GB)
Assigned to THE UNIVERSITY COURT OF THE UNIVERSITY OF EDINBURGH, Edinburgh (GB); and HERIOT-WATT UNIVERSITY, Edinburgh (GB)
Appl. No. 17/801,740
Filed by THE UNIVERSITY COURT OF THE UNIVERSITY OF EDINBURGH, Edinburgh (GB); and HERIOT-WATT UNIVERSITY, Edinburgh (GB)
PCT Filed Feb. 26, 2021, PCT No. PCT/GB2021/050500
§ 371(c)(1), (2) Date Aug. 23, 2022,
PCT Pub. No. WO2021/171037, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 2002869 (GB), filed on Feb. 28, 2020.
Prior Publication US 2023/0078471 A1, Mar. 16, 2023
Int. Cl. G01L 1/14 (2006.01); H05K 3/02 (2006.01); H05K 3/46 (2006.01)
CPC G01L 1/146 (2013.01) [G01L 1/144 (2013.01); H05K 3/02 (2013.01); H05K 3/4673 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of producing a flexible structure that comprises a plurality of thin-film layers of elastomeric material and at least one layer of micro-wrinkled electrically conductive material, the method comprising:
a) applying a selective anti-adhesion treatment process to a carrier substrate whereby an outer peripheral region of the substrate provides a strong adhesion region and the area of the substrate within the outer peripheral region provides an anti-adhesion central region;
b) forming, on the carrier substrate, a first plurality of successive thin-film layers of PDMS, each of the successive thin-film layers of PDMS having a smaller ratio of crosslinking agent to base material and hence a higher Young's modulus than a preceding one of the thin-film layer of PDMS;
c) forming, on the last-formed thin-film layer of PDMS, a first thin-film layer of Parylene;
d) placing the carrier substrate in an organic solvent for a first period of time to induce swelling in the first plurality of thin-film layers of PDMS;
e) forming, on the first thin-film layer of Parylene a first further thin-film layer of PDMS;
f) forming by vacuum deposition, on the first further thin-film layer of PDMS, a second thin-film layer of Parylene in which a permanent micro-scale wrinkled surface morphology is generated as a consequence of diffusion of the organic solvent from the first plurality of thin-film layers of PDMS during said vacuum deposition, thus providing a first micro-scale wrinkled Parylene layer;
g) forming and patterning a first layer of electrically conductive material on the first micro-scale wrinkled Parylene layer such that the first patterned electrically conductive material has a micro-scale wrinkled surface morphology conforming to that of the first micro-scale wrinkled Parylene layer, thus providing a first micro-scale wrinkled electrically conductive pattern layer.