A Method to Pattern Silver Nanowires Directly on Wafer-Scale PDMS Substrate and Its Applications

Abstract

This study describes a fabrication method of microsized AgNW patterns based on poly dimethylsiloxane (PDMS) substrate using a poly(p-xylylene) (parylene) stencil technique. Various patterns of AgNW conductive sheets were created on the wafer scale area in the forms of straight and serpentine lines, texts, and symbols, which dimensions ranged from a few tens of micrometers to hundreds of micrometers. We demonstrated the electrical performance of straight line and serpentine line patterned AgNW electrodes when subjected to mechanical strains. The gauge factor and stretchability ranged from 0.5 to 55.2 at 2% uniaxial strain and from 4.7 to 55.7%, respectively, depending on the shapes and structures of the AgNW electrodes. Using the developed AgNW patterning technique, we fabricated strain sensors to detect small body signals epidermally such as hand motion, eye blink and heart rate. Also, tactile sensors were fabricated and exhibited the sensitivity of 3.91 MPa(-1) in the pressure range lower than 50 kPa, and 0.28 MPa(-1) in the pressure range greater than 50 kPa up to 1.3 MPa. From these results, we concluded that the proposed technique enables the fabrication of reliable AgNW patterns on wafer-scale PDMS substrate and the potential applications for various flexible electronic devices.

Adhesion and Mechanical Properties of PDMS-Based Materials Probed with AFM: A Review

“…Strong polymer-filler interaction is responsible for improvement of the mechanical strength and hardness of the filled silicone elastomers. [50] Dissolving silver nanowires in PDMS used for fabrication of flexible films for electronic devises [85]. Gold nanoparticles block formation of chemical bond Si-O-Si and increase elasticity [86].…”

From stretchable to reconfigurable inorganic electronics

“…Various other studies have used copper as a metal layer on either polyimide, polyethylene naphthalate or PDMS for various applications, such as thermotherapy [165] , EEG recording [166] , RF interconnects [167] , lighting modules [168] and thin film inductors [169] . This design has also been successfully applied using other metal thin films, such as gold [170] , aluminum [171] , silver [172] , AgNWs [173] and ITO [174,175] . The mechanics of bending, stretching and stress strain distribution along the length of springs have been well studied for the meandering spring architecture [178][179][180][181] .…”

Monolithically integrated stretchable photonics

“…This unique feature combines the best of both worlds: for example, we can take advantage of the reduced propagation loss in low-index-contrast optics while leveraging high-index-contrast (HIC) elements to attain tight optical confinement and superior diffraction efficiency. The material choices further enable monolithic photonic integration on elastomeric substrates, formerly considered a challenging task due to the gigantic coefficient of thermal expansion (CTE) of elastomers 25 , 26 , 27 , 28 , which is one to two orders of magnitude larger than those of inorganic semiconductor and dielectric materials.…”