Efficient exfoliation of UV-curable, high-quality graphene from graphite in common low-boiling-point organic solvents with a designer hyperbranched polyethylene copolymer and their applications in electrothermal heaters

Te Hu; Huijian Ye; Zhenggang Luo; Junjie Ma; Boyuan Zhang; Xuanhe Zhang; Jinwei Song; Qingping Wang; Lixin Xu

doi:10.1016/j.jcis.2020.02.068

Efficient exfoliation of UV-curable, high-quality graphene from graphite in common low-boiling-point organic solvents with a designer hyperbranched polyethylene copolymer and their applications in electrothermal heaters

J Colloid Interface Sci. 2020 Jun 1:569:114-127. doi: 10.1016/j.jcis.2020.02.068. Epub 2020 Feb 17.

Authors

Te Hu¹, Huijian Ye², Zhenggang Luo¹, Junjie Ma¹, Boyuan Zhang¹, Xuanhe Zhang¹, Jinwei Song¹, Qingping Wang¹, Lixin Xu³

Affiliations

¹ College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
² College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China; Pinghu Institute of Advanced Materials, Zhejiang University of Technology, Pinghu 314212, China. Electronic address: huy19@zjut.edu.cn.
³ College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China; Pinghu Institute of Advanced Materials, Zhejiang University of Technology, Pinghu 314212, China. Electronic address: gcsxlx@zjut.edu.cn.

PMID: 32105899
DOI: 10.1016/j.jcis.2020.02.068

Abstract

The use of stabilizer with designer structures can effectively promote graphite exfoliation in common solvents to render functionalized graphene desirable for their various applications. Herein, a hyperbranched polyethylene copolymer, HBPE@Py@Acryl, simultaneously bearing multiple pyrene terminal groups and pendant acryloyl moieties has been successfully synthesized from ethylene with a Pd-diimine catalyst based on unique chain walking mechanism. The unique structural design of the HBPE@Py@Acryl makes it capable of effectively promote graphite exfoliation in a series of common, low-boiling-point organic solvents, e.g. CHCl₃, to render stable graphene dispersions with concentrations effectively adjustable by changing feed concentrations of graphite and polymer or sonication time. Meanwhile, it can be irreversibly adsorbed on the exfoliated graphene surface based on the π-π interactions between them to concurrently render acryloyl-functionalized graphene free of structural defects, with majority (92.7%) of them having a thickness of 2-3 layers. This allows us to obtain graphene electrothermal films simply by filtration and UV irradiation, which exhibit outstanding stability in use. The action mechanism of the HBPE@Py@Acryl as stabilizer for promoting graphite exfoliation and the role of UV irradiation on improving the stability in use of resulting graphene films have been elucidated.

Keywords: Electrothermal heaters; Hyperbranched polyethylene copolymer; Liquid-phase exfoliation; Low-boiling-point organic solvents; UV-curable graphene.