Investigation and modeling of the electrical properties of poly (methyl methacrylate)/graphene nanoplatelets composite sheets with various thickness

Luo X, Schubert DW (2021)

Publication Language: English

Publication Type: Conference contribution, Abstract of a poster

Publication year: 2021

Event location: Stockholm SE

Abstract

Poly(methyl methacrylate) (PMMA) composites containing graphene nanoplatelets (GNPs) at various concentrations were melt mixed and hot pressed into rectangular sheets with a variety of thickness. The conductivity σ in the in-plane and perpendicular directions were investigated and modeled using McLachlan general effective medium (GEM) equation. In the in-plane direction, the values of the parameter t and the resultant percolation thresholds Φc, I of composite sheets were almost constants of 2.90 vol. % and 2.0 (universal value), respectively, regardless of the sample thickness. In the perpendicular direction, the exponent t decreased from 3.5 to 2.8 as the thickness increased from 0.2 mm to 2 mm, while the percolation threshold Φc, P increased from 2.12 vol. % to 2.72 vol. %. The lower Φc, P reveals an easier formation of the percolated network within thinner samples. This is likely due to the large aspect ratio (AR) of GNPs, the lower Φc, P values relative to Φc, I also confirm the dependence of sample geometry. The parameter t could be termed the “shape factor”, a higher value indicates more tunneling effect or/and more tortuous networks. From the point view of tunneling effect, it is considered that more electron tunneling occurred in the perpendicular direction for composite sheets with lower thickness, which was resulted from more thin layers of insulating polymer between the graphene sheets. The finding is opposite to that of the previous study on PMMA/carbon fibers (CF) composites, which might be ascribed to the different shapes of GNPs and CF. Flake-like GNPs were more prone to construct direct conductive pathways in long-distance transport than rod-like CF.

Authors with CRIS profile

Xiaoling Luo Lehrstuhl für Werkstoffwissenschaften (Polymerwerkstoffe) (LSP) Dirk Schubert Lehrstuhl für Werkstoffwissenschaften (Polymerwerkstoffe) (LSP)

How to cite

APA:

Luo, X., & Schubert, D.W. (2021, October). Investigation and modeling of the electrical properties of poly (methyl methacrylate)/graphene nanoplatelets composite sheets with various thickness. Poster presentation at Advanced Nanomaterials Congress, Stockholm, SE.

MLA:

Luo, Xiaoling, and Dirk W. Schubert. "Investigation and modeling of the electrical properties of poly (methyl methacrylate)/graphene nanoplatelets composite sheets with various thickness." Presented at Advanced Nanomaterials Congress, Stockholm 2021.

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