A Facile and Rapid Approach to Lotus‐Seedpod‐Structured Electronic Skin for Monitoring Diverse Physical Stimuli

Abstract

Although the burgeoning Internet of Things has created soaring demand for electronic skin (e‐skin), a facile and eco‐friendly approach towards the scalable fabrication of the hierarchical active layer for such a system is still limited in the stage of development. Herein a sensing layer with lotus‐seedpod‐like structures is reported that is readily prepared by multi‐melt multi‐injection molding (M3IM). Because of the shear flow and thermodynamic factors in M3IM, silica microspheres in the core layer of the polyethylene/silica composite are inclined to migrate to the interface between the skin layer of ethylene‐α‐octene block copolymer/carbon nanotube composite and core layer, resulting in lotus‐seedpod‐like structures consisting of micro‐pits and asperities formed on the surface of the peeled skin layer. The sensitivity of the fabricated e‐skin is significantly affected by the number of micro‐pits on the lotus‐seedpod‐like structure, which mainly depend on the silica mass fraction in the composites. For instance, the e‐skin made from the composites with 66.67 wt% silica exhibits a sensitivity of 19.87 kPa−1 over a wide linear range of 0.017–11.5 kPa and demonstrates excellent durability and reproducibility, enabling multiple signal detection. This work sheds light on the rapid and scalable fabrication of sensors using a polymer melt processing strategy.

Topography‐Supported Nanoarchitectonics of Hybrid Scaffold for Systematically Modulated Bone Regeneration and Remodeling

“…[ 6,25,40 ] However, iii) the ceramic nanoparticles could reversibly float toward the adjacent surface (adlayer) of the polymeric substance as a solid because of the suspension‐balancing effect. [ 25,41 ] Simultaneously, there were no chemical reactions between the ceramic reinforcement and polymeric matrix; thus, the TiO 2 nanoparticles agglomerated into their original state via van der Waals interactions, which decreased the surface energy. [ 40 ] After expulsive migration (suspension‐balancing effect) toward the PEEK adlayer in the diffusive environment of the polymer fluid, ceramic agglomeration became more prevalent on the solidified polymer, thereby forming a constrained protuberant morphology of the structure (Figure S2c,d, Supporting Information).…”

Recent advances in smart wearable sensors as electronic skin

“…58 In addition, a novel architecture was developed for pressure sensing. 59 Innovation in material fabrication 61 and using PDMS films coated with AgNWs 60 have proved to be effective in enhancing many features of e-skin sensory function. Sensitive 3D printed conductive ink with gel-like behavior made of graphene and PDMS microspheres can sense pressure and accurately distinguish the surface topography.…”

“…57 In another attempt, silica microspheres were incorporated in the core layer of the polyethylene/silica composite and ethylene-α-octene block co-polymer/carbon nanotube composite. 61 The glycerol-coated electrospun silk protein with water-vapor permeability, a highly thermal-wet electrode for on-skin electrophysiological monitoring with sweat tolerance, was also used to enhance the features of e-skin. 227 Liu et al applied a dual network hydrogel of poly(β-cyclodextrin), triethylene glycol (TEG), poly(vinyl alcohol), 63 while others preferred to use CareGum consisting of polydopamine (PDA) and PVA and ferric ions (Fe 3+ ).…”

Ta4C3 Nanosheet/Melamine Sponges with High Sensitivity and Long-Term Stability for Wearable Piezoresistive Sensors

“…1 Flexible and wearable strain sensors have emerged as an important type of device in wearable technology, offering advantages over traditional bulky and rigid sensors. 2 These sensors possess the ability to detect various stimuli relevant to the human body with high sensitivity and fast response time. 3 Strain sensors can be categorized into three types based on the electrical signal transformed by mechanical stress: piezoelectric, 4 capacitive, 5 and piezoresistive sensors.…”

“…The real-time detection of human physiology through accurate sensors has attracted significant attention for its application in personal health care . Flexible and wearable strain sensors have emerged as an important type of device in wearable technology, offering advantages over traditional bulky and rigid sensors . These sensors possess the ability to detect various stimuli relevant to the human body with high sensitivity and fast response time .…”