Open AccessAl2O3 Dispersion-Induced Micropapillae in an Epoxy Composite Coating and Implications in Thermal Conductivity
Author(s) -
Zihe Pan,
Yanhong Liu,
Fei Wang,
Guangjun Lu,
Fengling Yang,
Fangqin Cheng
Publication year - 2021
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.1c01282
Subject(s) - epoxy , materials science , composite material , particle size , composite number , thermal conductivity , particle (ecology) , dispersion (optics) , coating , conductivity , particle size distribution , aggregate (composite) , chemical engineering , chemistry , oceanography , physics , optics , engineering , geology
Al 2 O 3 particles with different sizes were dispersed into an epoxy precursor to improve the thermal conductivity (TC) of the epoxy coating. Al 2 O 3 particles tend to aggregate in epoxy, and the aggregation becomes more apparent (formation of micropapillae when the particle size is larger than 1 μm) with the increase of particle size. The calculated fast aggregation rates of various-size Al 2 O 3 particles in epoxy showed that the fast aggregation rate increased to a maximum rate of 6.37 × 10 -20 m 3 ·s -1 at a particle size of 200 nm and then decreased to a plateau value with the increase of particle size. The high fast aggregation rate caused the aggregation and the formation of nano- and micropapillae, causing the heterogeneous distribution of Al 2 O 3 particles. These micropapillae were separated by epoxy, which made formation of continuous pathways fail, causing the reduction of TC and heterogeneous heat distribution. The highest thermal conductivity of 2.52 W/m·K and uniform heat distribution were observed at the optimum filler size of 30 nm. The research findings provide the knowledge of optimizing particle size on constructing a thermally conductive polymer composite.