Solid-state cooling by elastocaloric polymer with uniform chain-lengths

Shixian Zhang,Chenjian Li,Qing Wang,Zhiwei Ye,Wenqing Zhang,Qi Li,Yuheng Fu,Shan Wang,Quanling Yang,Huaqing Zhang,Xingnan Zhou,Chuanxi Xiong,Tao Wang

doi:10.1038/s41467-021-27746-y

Shixian Zhang, Chenjian Li + Show 11 more

Open Access

https://doi.org/10.1038/s41467-021-27746-y

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Abstract

Although the elastocaloric effect was found in natural rubber as early as 160 years ago, commercial elastocaloric refrigeration based on polymer elastomers has stagnated owing to their deficient elastocaloric effects and large extension ratios. Herein, we demonstrate that polymer elastomers with uniform molecular chain-lengths exhibit enormous elastocaloric effects through reversible conformational changes. An adiabatic temperature change of −15.3 K and an isothermal entropy change of 145 J kg−1 K−1, obtained from poly(styrene-b-ethylene-co-butylene-b-styrene) near room temperature, exceed those of previously reported elastocaloric polymers. A rotary-motion cooling device is tailored to high-strains characteristics of rubbers, which effectively discharges the cooling energy of polymer elastomers. Our work provides a strategy for the enhancement of elastocaloric effects and could promote the commercialization of solid-state cooling devices based on polymer elastomers.

Highlights

The elastocaloric effect was found in natural rubber as early as 160 years ago, commercial elastocaloric refrigeration based on polymer elastomers has stagnated owing to their deficient elastocaloric effects and large extension ratios
The σ of a polymer working medium is one or two orders of magnitudes smaller than those applied to shape-memory alloys (SMAs), but the commercialization of elastocaloric refrigeration based on polymertension technology is obstructed by their low E-caloric effects (CEs)
The ΔTadi associated with the elastocaloric effects (E-CEs) in the thermoplastic elastomers (TPEs) was induced under a uniaxial-strain-controlled system in an open indoor environment (Methods, Supplementary Fig. 2)

Summary

Introduction

The elastocaloric effect was found in natural rubber as early as 160 years ago, commercial elastocaloric refrigeration based on polymer elastomers has stagnated owing to their deficient elastocaloric effects and large extension ratios. We demonstrate that polymer elastomers with uniform molecular chain-lengths exhibit enormous elastocaloric effects through reversible conformational changes. Our work provides a strategy for the enhancement of elastocaloric effects and could promote the commercialization of solid-state cooling devices based on polymer elastomers. Due to the enormous elastocaloric effects (E-CEs) found in the martensitic transition of shape-memory alloys (SMAs) around room temperature[16–20], solid-state cooling technology based on E-CEs is considered to be the best promising alternative to conventional refrigeration devices[21–24]. The conformational changes of the integrated network chains in a polymer working medium from curled to straight would be astronomical, which would result in enormous E-CEs. the conformational changes during the uniaxial tensile processes of elastomers are constrained by the uniformity of the molecular chain-length. A rotary-motion cooling device was tailored to highstrains characteristics of rubbers, which effectively discharged the cooling energy of polymer elastomers

Methods

Results

Conclusion