Surface Wrinkling for Flexible and Stretchable Sensors

Abstract

Figure 11. Other fabricating methods to develop flexible or stretchable sensors. a) Left: Fabrication of a flexible sensor by thermal oxidation of copper foil to produce the wrinkled morphology. Right:As-prepared sensing layer with wrinkled structures on the surface and its pressure sensing performance (Reproduced with permission. [10] Copyright 2016, Wiley-VCH). b) Top: Wrinkling mechanism by evaporation of water droplets. Bottom: Atomic force microscopy images of the monolayer graphene with wrinkled geometry (Reproduced with permission. [87] Copyright 2020, Nature Publishing Group). c) Left: Schematic diagram of the wrinkling phenomenon by electrospinning. Right: Scanning electron microscopy (SEM) images of the wrinkled surfaces (Reproduced with permission. [88] Copyright 2020, Elsevier). d) Left: Preparation steps and schematic representation of hierarchical wrinkled conductors. Right: SEM images and illustrations of hierarchical wrinkles (Reproduced with permission. [89] Copyright 2016, Wiley-VCH).

Flexible Azo-Polyimide-Based Smart Surface with Photoregulatable Surface Micropatterns: Toward Rewritable Information Storage and Wrinkle-Free Device Fabrication

“…Among them, photoresponsive materials have attracted extensive attention because light is a kind of green and environmentally friendly clean energy that can be regulated remotely, rapidly, and accurately. 13−17 Compared to the photoresponsive inorganic transition-metal oxide, photoresponsive organic molecules with reversible conformational changes, such as spiropyran, 18,19 diarylethenes, 20,21 and azobenzene, 22−26 have been widely used in controllable liquid transport, 11 information storage, 27 sensors, 28 anticounterfeiting, 29,30 etc. In particular, the azobenzene and its derivatives demonstrate the obvious variation of the spatial structure and the dipole moments between the stable trans state and the metastable cis state, which endows the azobenzene-containing materials with fascinating properties of a reversible structural change or surface properties upon photoirradiation.…”

Laser Micro/Nano‐Structuring Pushes Forward Smart Sensing: Opportunities and Challenges

“…Such structural or compositional variations and their cooperations could accelerate the interaction of sensing materials with analytes or stimuli and amplify the conversion of generated signals, from both chemistry and physics, finally offering the possibility for the optimization and improvement of sensor performance. [1,7,19,22,33,34] Accordingly, a wide range of sensors based on laser-texturing micro/nanostructures have been achieved and explored extensively, which is being used in wearable devices in biomedicine, energy, and environment field. The continuous innovation of laser micro/ nanofabrication will fuel the progress of making sensors smarter.…”

An ultra-thin flexible wearable sensor with multi-response capability prepared from ZIF-67 and conductive metal–organic framework composites for health signal monitoring

“…[41][42][43] More recently, a structure-based design has reported a resistive haptic sensor with increased sensitivity and linearity. [44][45][46] Moreover, most of these sensors use a typical structure of two thin films coated with conductive materials to make full use of the change in contact resistance between the films. When pressure is applied to the sensor, the contact area between the two films increases dramatically, resulting in a significant increase in current.…”