Multilayer Stretchable Films for Flexible Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stretchable substrates for electronics face challenges such as poor printability, ink curing stability, and mechanical properties due to issues like hydrolytic stability, weatherability, and high coefficient of thermal expansion, limiting their application in flexible and stretchable devices.
Innovation Solution
Development of extruded or coextruded multilayer films using a blend of polyester elastomer and cycloaliphatic polymer components, with specific molecular compositions and orientations, to achieve excellent mechanical properties and printability, suitable for flexible and stretchable electronic substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDMS is used as stretchable substrate, then biocompatibility and thermal stability are improved, but printability deteriorates due to poor wettability and adhesion
Solution Approach 1:
The patent uses composite materials by combining PDMS with a release liner that has specific surface properties. The release liner acts as an intermediate layer that provides both good adhesion for printing and easy release of the printed circuit, resolving the contradiction between maintaining PDMS biocompatibility/thermal stability and achieving printability.
2Manufacturing precision
If photolithography is used for device fabrication on elastomeric substrates, then device patterning is achieved, but device delamination occurs due to solvent swelling of PDMS
Solution Approach 1:
The release liner serves as an intermediary layer between the PDMS substrate and the printed circuit devices. It allows photolithography processing to proceed while preventing direct solvent contact with PDMS, thus avoiding swelling and delamination. The liner provides a barrier function that decouples the processing requirements from the substrate material constraints.
3Adaptability or versatility
If PDMS is used as substrate, then stretchability is achieved, but dimensional stability deteriorates due to high CTE causing noticeable dimension variation during temperature cycles
Solution Approach 1:
The patent addresses dimensional stability by controlling the crosslink density and composition of the PDMS network, and by using a release liner with matched thermal expansion properties. These parameter changes allow the system to maintain stretchability while reducing excessive dimensional variation during temperature cycling.
4Ease of manufacture
If TPU is used as stretchable substrate, then printability is improved, but hydrolytic stability and weatherability deteriorate
Solution Approach 1:
The release liner acts as a protective intermediary that shields the TPU substrate from environmental degradation. It provides a barrier against moisture and UV exposure, preventing hydrolysis and weathering of the TPU, while still allowing printing processes to occur on the TPU surface.
Data Source
AI summary
Herein disclosed are s extruded and multilayer films suitable for use as a substrate for printed circuits that afford the simultaneous achievement of both excellent mechanical properties, printability and ink curing stability, flexability and stretchability, and electronic performance. The films can be prepared from cycloaliphatic polymers and polyester elastomers.