title: Flexible Infrared Responsive Multi-Walled Carbon Nanotube/Form-Stable Phase Change Material Nanocomposites.
abstract: Flexible infrared (IR)-responsive materials, such as polymer nanocomposites, that exhibit high levels of IR responses and short response times are highly desirable for various IR sensing applications. However, the IR-induced photoresponses of carbon nanotube (CNT)/polymer nanocomposites are typically limited to 25%. Herein, we report on a family of unique nanocomposite films consisting of multi-walled carbon nanotubes (MWCNTs) uniformly distributed in a form-stable phase change material (PCM) that exhibited rapid, dramatic, reversible, and cyclic IR-regulated responses in air. The 3 wt % MWCNT/PCM nanocomposite films demonstrated cyclic, IR-regulated on/off electrical conductivity ratios of 11.6 ± 0.6 and 570.0 ± 70.5 times at IR powers of 7.3 and 23.6 mW/mm(2), respectively. The excellent performances exhibited by the MWCNT/PCM nanocomposite films were largely attributed to the IR-regulated cyclic and reversible form-stable phase transitions occurring in the PCM matrix due to MWCNT's excellent photoabsorption and thermal conversion capabilities, which subsequently affected the thickness of the interfacial PCM between adjacent conductive MWCNTs and thus the electron tunneling efficiency between the MWCNTs. Our findings suggest that these unique MWCNT/PCM nanocomposites offer promising new options for high-performance and flexible optoelectronic devices, including thermal imaging, IR sensing, and optical communication.
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institute for Discovery, and Materials Science Program and ‡Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Yunming
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institute for Discovery, and Materials Science Program and ‡Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Hongyi
authors.initials: H
authors.lastname: Mi
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institute for Discovery, and Materials Science Program and ‡Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institute for Discovery, and Materials Science Program and ‡Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institute for Discovery, and Materials Science Program and ‡Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Shaoqin
authors.initials: S
authors.lastname: Gong
keywords: IR responsive electrical conductivity; flexible photoelectronics; form-stable phase change materials; multi-walled carbon nanotubes; polymer nanocomposites