Melding Vapor-Phase Organic Chemistry and Textile Manufacturing To Produce Wearable Electronics Published as part of the Accounts of Chemical Research special issue “Wearable Bioelectronics: Chemistry, Materials, Devices, and Systems”. Trisha L. Andrew,* ,†,∥ Lushuai Zhang, † Nongyi Cheng, ‡ Morgan Baima, † Jae Joon Kim, †,§ Linden Allison, † and Steven Hoxie † † Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States ‡ Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States § Department of Polymer Science & Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States ∥ Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States CONSPECTUS: Body-mountable electronics and electronically active garments are the future of portable, interactive devices. However, wearable devices and electronic garments are demanding technology platforms because of the large, varied mechanical stresses to which they are routinely subjected, which can easily abrade or damage microelectronic components and electronic interconnects. Furthermore, aesthetics and tactile perception (or feel) can make or break a nascent wearable technology, irrespective of device metrics. The breathability and comfort of commercial fabrics is unmatched. There is strong motivation to use something that is already familiar, such as cotton/silk thread, fabrics, and clothes, and imperceptibly adapt it to a new technological application. 24 Especially for smart garments, the intrinsic breathability, comfort, and feel of familiar fabrics cannot be replicated by devices built on metalized synthetic fabrics or cladded, often-heavy designer fibers. We propose that the strongest strategy to create long-lasting and impactful electronic garments is to start with a mass-produced article of clothing, fabric, or thread/yarn and coat it with conjugated polymers to yield various textile circuit components. Commonly available, mass-produced fabrics, yarns/threads, and premade garments can in theory be transformed into a plethora of comfortably wearable electronic devices upon being coated with films of electronically active conjugated polymers. The definitive hurdle is that premade garments, threads, and fabrics have densely textured, three-dimensional surfaces that display roughness over a large range of length scales, from microns to millimeters. Tremendous variation in the surface morphology of conjugated-polymer-coated fibers and fabrics can be observed with different coating or processing conditions. In turn, the morphology of the conjugated polymer active layer determines the electrical performance and, most importantly, the device ruggedness and lifetime. Reactive vapor coating methods allow a conjugated polymer film to be directly formed on the surface of any premade garment, prewoven fabric, or fiber/yarn substrate without the need for specialized processing conditions, surface pretreatments, detergents, or fixing agents. This feature allows electronic coatings to be applied at the end of existing, high-throughput textile and garment manufacturing routines, irrespective of dye content or surface finish of the final textile. Furthermore, reactive vapor coating produces conductive materials without any insulating moieties and yields uniform and conformal films on fiber/fabric surfaces that are notably wash- and wear- stable and can withstand mechanically demanding textile manufacturing routines. These unique features mean that rugged and practical textile electronic devices can be created using sewing, weaving, or knitting procedures without compromising or otherwise affecting the surface electronic coating. In this Account, we highlight selected electronic fabrics and garments created by melding reactive vapor deposition with traditional textile manipulation processes, including electrically heated gloves that are lightweight, breathable, and sweat-resistant; surface-coated cotton, silk, and bast fiber threads capable of carrying large current densities and acting as sewable circuit interconnects; and surface-coated nylon threads woven together to form triboelectric textiles that can convert surface charge created during small body movements into usable and storable power. ■ INTRODUCTION Body-mountable electronics and electronically active garments are the future of portable, interactive devices. 1 Recent reports of wearable devices and garments that allow advanced physiological and performance monitoring, 2−5 new touch/user interfaces, 6−8 portable power generation, 9 and energy storage 10 represent a few of the sophistications promised by these nascent technologies. However, wearable devices and electronic garments are demanding technology platforms. Wearable devices are subject to large, varied mechanical stresses that can easily abrade or damage microelectronic components, particularly electronic interconnects. 11 Consequently, soft electronic materials, partic- ularly conjugated organic polymers, are enabling electronic Received: December 1, 2017 Published: March 9, 2018 Article pubs.acs.org/accounts Cite This: Acc. Chem. Res. 2018, 51, 850-859 © 2018 American Chemical Society 850 DOI: 10.1021/acs.accounts.7b00604 Acc. Chem. Res. 2018, 51, 850−859 Downloaded via UNIV OF MASSACHUSETTS AMHERST on August 1, 2018 at 23:09:36 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.