Soft Elastomers with Programmable Stiffness as Strain-Isolating Substrates for Stretchable Electronics

Abstract

Stretchable electronics are of rapidly increasing interest due to their unique ability to function under complex deformations. Strain isolation of stiff functional components from the substrate represents a key challenge in the development of stretchable electronics since their mechanical mismatch may yield undesirable strains to degrade the device performance. The results presented here report an approach to develop a soft strain-isolating polymer substrate with programmable stiffness by spatioselective ultraviolet exposure for stretchable electronics. The approach being compatible with the well-established lithographic process reduces the fabrication complexity significantly and offers a simple yet robust strain-isolation mechanism to ensure the system stretchability of more than 100%. Combined experimental and numerical studies reveal the fundamental aspects of the design, fabrication, and operation of the strain-isolating substrate. Demonstration of this concept in a stretchable inorganic metal-based resistive temperature sensor and a stretchable organic photodiode array with unusually high performance shows the simplicity of the approach and the robustness in strain isolation in both component and device levels. This type of strain-isolation design not only creates promising routes for potential scalable manufacturing of stretchable electronics but also engineering opportunities for stretchable electronics involving the integration of various functional components, which require the quantitative control of the strain levels to achieve optimal performance.

PVDF-TrFE-Based Stretchable Contact and Non-Contact Temperature Sensor for E-Skin Application

“…Other techniques have been developed and can be implemented in this device to extend its stretchability. Cai et al, have worked on the rigidification of specific areas of the substrates to avoid deformation [35].…”

Development of a Flex and Stretchy Conductive Cotton Fabric Via Flat Screen Printing of PEDOT:PSS/PDMS Conductive Polymer Composite

“…Flat screen printing was preferred for this work because attaining the required conductive polymer composite paste viscosity and transferring it to the substrate by this technique is straightforward. Other possible techniques that could be explored are transfer printing [22], while also mechanics designs via transfer printing may provide another effective route toward stretchable conductive fabric [23].…”

Recent Advances on Thermal Management of Flexible Inorganic Electronics

“…The challenge to develop flexible inorganic electronic devices (FIEDs) lies in the mismatch between the intrinsic brittle inorganic electronic material (e.g., silicon) and the flexibility requirement in applications. One effective strategy to overcome this mismatch is to integrate the functional inorganic electronic material in a stretchable format [6][7][8][9][10][11][12] at strategic locations on a soft polymer substrate by advanced transfer printing techniques [13][14][15][16]. Due to the unique mechanical properties of FIEDs, they can have conformal contacts with biological tissues under complex deformations, which enable the real-time monitoring of human vital signs for early diagnosis [17].…”