Advanced polymer materials‐based electronic skins for tactile and non‐contact sensing applications

Abstract

Recently, polymer materials have been at the forefront of other materials in building high-performance flexible electronic skin (e-skin) devices due to conspicuous advantages including excellent mechanical flexibility, good compatibility, and high plasticity. However, most research works just paid considerable attention and effort to the design, construction, and possible application of e-skins that reproduce the tactile perception of the human skin sensory system.Compared with tactile sensing devices, e-skins that aim to imitate the noncontact sensing features in the sensory system of human skin tend to avoid undesired issues such as bacteria spreading and mechanical wear. To further promote the development of e-skins to the human skin sensory system where tactile perception and non-contact sensing complement each other, significant progress and advances have been achieved in the field of polymer materials enabled e-skins for both tactile perception and non-contact sensing applications.In this review, the latest progress in polymer material-based e-skins with regard to tactile, non-contact sensing capabilities and their practical applications are introduced. The fabrication strategies of polymer materials and their role in building high-performance e-skins for tactile and non-contact sensing are highlighted. Furthermore, we also review the research works that integrated the polymer-based tactile and non-contact e-skins into robots and prostheses, smart gloves, and VR/AR devices and addressed some representative problems to demonstrate their suitability in practical applications in human-machine interactions. Finally, the current challenges in the construction of high-performance tactile and non-contact e-skins are highlighted and promising properties in this direction, by taking advantage of the polymer materials, are outlined.

Latest developments and trends in electronic skin devices

“…Figures 3C, 4D, 5A, 5B, 6C, 12A, 12C, 13A, 13C a nd 14A are cited from the researches in refs. [62,72,82,83,95,199,200,215,217,224,225] , respectively, showing partial body parts of the participants in the experiment. The purpose of these citations is to present the relevant research results and experimental methods more intuitively.…”

“…Sun et al proposed a green and sustainable one-pot synthesis method by in situ photopolymerization of polymerizable deep eutectic solvents (PDES)treated cellulose pulp, and the prepared cellulose-based Ion conductors (ICs), PDES/cellulose microfibers (CMFs), exhibited very high stretchability (3,210% ± 302%), high ionic conductivity (0.09 S•m -1 ), high toughness (13.17 ± 2.32 MJ•m -3 ), strong self-healing ability, good stability, and compatibility with human skin [216] . The detection of typical human strain signals and ECG signals using flexible electrodes prepared [215] ; (B) schematic diagram of the preparation process, gesture detection, and detection of ECG signals of the PDES/CMFs flexible electrodes [216] ; (C) schematic diagram of the architecture, composition and working process of the wireless electronic skin clinical detection system [217] . PU: Polyurethane; PVA: polyvinyl alcohol; MF-CH: microfiber composite hydrogel; PET: polyethylene terephthalate; PI: polyimide; PDMS: polydimethylsiloxane; NF: nanofiber; CMFs: cellulose microfibers; AMP: alkalized MXenes/polydopamine; EMG: electromyogram; MF: microfiber; ECG: electrocardiogram.…”

“…As shown in Figure 13C, Cho et al reported an e-skin system consisting of a multimodal sensor system and a wireless detection system (using the RF430FRL152H NFC SoC chip from Texas Instruments) for continuously monitoring pressure, temperature, and hydration at skin interfaces of a patient in a wheelchair [217] . The multimodal sensor system includes a pressure sensor, a temperature sensor, and a galvanic skin response sensor.…”

Thermogalvanic organohydrogel-based non-contact self-powered electronics for advancing smart agriculture

“…[1][2][3] Currently, most traditional sensors operate in a direct contact mode or deformation mode, which inevitably deteriorates their stability, reliability, and service life owing to biological contaminants, chemical stains, and mechanical wear. [4][5][6][7][8] On the contrary, non-contact sensors/ equipment, especially those employed in harsh environments, such as farms and factories, can effectively avoid biological and chemical contamination from external environments. [9][10][11][12] Moreover, the demand for an external power supply for most sensors restricts their utilization owing to frequent battery charging or replacement, causing problems of limited life span and environmental contamination.…”

A selectively bimodal flexible sensor based on IL/SWCNTs/PEDOT:PSS nanocomposites for materials and shape recognition

“…). 1–6 For instance, Yan et al used a manipulator to explore various objects on its own initiative. 7 In addition, it is known that the primary origin of the human hand skin, which can effortlessly distinguish the fine information of various objects, is mainly ascribed to the high-selective perception of mechanoreceptors (force stimuli) and thermoreceptors (temperature stimuli).…”