Subscriber access provided by UNIV OF ARIZONA
Article
Self-Healing, Highly Sensitive Electronic Sensors Enabled by Metal-Ligand Coordination and Hierarchical Structure Design Yangyang Han, Xiaodong Wu, Xinxing Zhang, and Canhui Lu ACS Appl. Mater. Interfaces, Just Accepted Manuscript • Publication Date (Web): 24 May 2017 Downloaded from http://pubs.acs.org on May 25, 2017
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 34
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Applied Materials & Interfaces
Self-Healing, Highly Sensitive Electronic Sensors Enabled by Metal-Ligand Coordination and Hierarchical Structure Design Yangyang Han, Xiaodong Wu, Xinxing Zhang,* and Canhui Lu* State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, No.24 South Section 1 of First Ring Road, Cheng Du 610065, China Keywords: sensor, self-healing, elastomer, metal-ligand coordination, hierarchical structure
Abstract
Electronic sensors capable of capturing mechanical deformation are highly desirable for next generation of artificial intelligence products. However, it remains a challenge to prepare selfhealing, highly sensitive and cost-efficient sensors for both tiny and large human motion monitoring. Here, a new kind of self-healing, sensitive, and versatile strain sensors has been developed by combining metal-ligand chemistry with hierarchical structure design. Specifically, a self-healing and nanostructured conductive layer is deposited onto a self-healing elastomer substrate cross-linked by metal-ligand coordinate bonds, forming a hierarchically structured sensor. The resultant sensors exhibit high sensitivity, low detection limit (0.05% strain), remarkable self-healing capability as well as excellent reproducibility. Notably, the self-healed
ACS Paragon Plus Environment
1
ACS Applied Materials & Interfaces
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 34
sensors are still capable to precisely capture not only tiny physiological activities (such as speech, swallowing and coughing) but also large human motions (finger and neck bending, touching). Moreover, harsh treatments, including bending over 50000 times and mechanical washing, could not influence the sensitivity and stability of the self-healed sensors in human motion monitoring. This proposed strategy via alliance of metal-ligand chemistry and hierarchical structure design represents a general approach to manufacturing self-healing, robust sensors and other electronic devices.
1. Introduction
Strain sensors that can detect fairly small physical movement and mechanical deformation are widely used in the fields of smart electronic devices for various applications, such as healthcare,1,2 human-machine interfaces,3,4 robotics,5,6 wearable devices,7,8 etc. Generally, strain sensors detect mechanical deformation based on the variation in their resistance, capacitance and other electrical parameters under external stain stimuli.9 Good stability and excellent reproducibility are highly necessary for desirable strain sensors. However, overuse, incidental scratches or mechanical cuts may cause mechanical and electrical damages to strain sensors during their service lifetime.10-13 These fatal damages could lead to failure of the sensors and even disastrous accidents in certain fields. Therefore, it is pivotal to endow strain sensors with additional abilities of spontaneously repairing both mechanical and electrical damages, which could potentially improve their reliability and safety and extend their lifespan. In recent years, many strategies have been exploited to impart sensors with self-healing ability. For instance, Bao et al. successfully prepared self-healing electronic sensor skin via hydrogen interactions with nickel particles as conductive fillers.14 Zhang et al. developed self-healing
ACS Paragon Plus Environment
2
Page 3 of 34
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Applied Materials & Interfaces
conductive elastomers and proximity sensor through host-guest interactions.15 Lee et al. reported stretchable self-healing strain sensors based on conductive dynamic cross-linked hydrogels.16 In these works, the fabricated sensors show desirable self-healing ability and could well restore their functional properties. However, these bulk materials exhibit relatively low sensitivity to tiny strains, which restricts their application in capturing subtle human motions, such as pronunciation and physiological activities. Recently, Haick et al. developed a self-healing sensing platform based on disulfide-cross-linked composites with gold nanoparticle film as a sensing layer, which could be used to detect small strain.17 Despite the aforementioned pioneering achievements, complex synthetic process and low mechanical strength (
