Automatic Transformation of Membrane‐Type Electronic Devices into Complex 3D Structures via Extrusion Shear Printing and Thermal Relaxation of Acrylonitrile–Butadiene–Styrene Frameworks

Abstract

This work demonstrates a means of automatic transformation from planar electronic devices to desirable 3D forms. The method uses a spatially designed thermoplastic framework created via extrusion shear printing of acrylonitrile-butadiene-styrene (ABS) on a stress-free ABS film, which can be laminated to a membrane-type electronic device layer. Thermal annealing above the glass transition temperature allows stress relaxation in the printed polymer chains, resulting in an overall shape transformation of the framework. In addition, the significant reduction in the Young's modulus and the ability of the polymer chains to reflow in the rubbery state release the stress concentration in the electronic device layer, which can be positioned outside the neutral mechanical plane. Electrical analyses and mechanical simulations of a membrane-type Au electrode and indium gallium zinc oxide transistor arrays before and after transformation confirm the versatility of this method for developing 3D electronic devices based on planar forms.

Materials Chemistry of Neural Interface Technologies and Recent Advances in Three-Dimensional Systems

“…As complements to these schemes for direct patterning, rolling and/or folding mechanisms allow formation of certain types of 3D architectures from 2D precursors, where transformation occurs by the action of engineered stresses in thin cantilevers or sheets. The required forces can arise from three main sources: capillarity, − thin-film residual stresses, − and active (i.e., stimuli-responsive) materials. ,− As an example of the first, heating of a metal solder (e.g., Sn, Pb–Sn) patterned along lines above its melting point leads to a change of shape to minimize its surface energy, resulting in folding or locking processes. , Figure e presents a submillimeter-scale polyhedron created by this type of self-folding assembly with an algorithmic design . Melting of electrodeposited solders (Pb–Sn; melting temperature 183 °C) on polygonal Ni panels moves hinges for each panel and results in self-folding at the edges of the 2D nets to create a self-assembled 3D geometry (1 mm height for the smallest feature).…”

“…Three-dimensional assembly induced by thin-film residual stresses uses mismatches in mechanical strains of stacked thin films (e.g., Si x N y , ZnO, TiO 2 , Al 2 O 3 , GaAs, Cr, vanadium dioxide (VO 2 ), germanium (Ge)). ,, Such multilayers can be prepared on substrates with sacrificial layers that, upon their removal, lead to self-rolling to form tubular, scroll-like, or polyhedral geometries. This process can transform microfabricated 2D electronic structures into 3D geometries for various applications (e.g., energy, , optoelectronics, , electronics, ,− biological studies − ). Thin, tubular SiNM-based photodetectors exhibit 1000 times enhancements in photoresponsivity compared to 2D devices due to light-trapping effects.…”