Study on the dispersibility of carbonyl iron powder in polydimethylsiloxane-based composites in the perspective of Gibbs free wetting energy

Abstract

• The CIP was covered with various DDSA concentrations. • Increased DDSA content reduced the CIP surface energy. • The CIP wettability improved with the DDSA addition. • The effect of DDSA was saturated at 0.5 wt% of DDSA. • The CIP dispersibility in PDMS composites was optimized at 0.5 wt% of DDSA. Enhancing the dispersibility of carbonyl iron powder (CIP) in polydimethylsiloxane (PDMS) is important for achieving high-performance CIP-based PDMS composites. The dispersibility of CIPs in the PDMS composites was explored in the perspective of Gibbs free wetting energy (ΔG). The CIP was coated with various wt% of dodecenylsuccinic anhydride (DDSA) from 0 to 1.0 wt%. The surface energy of CIP decreased as the DDSA increased up to 0.5 wt%, after which no further decrease in surface energy was observed. ΔG was calculated based on the measured surface characteristics, which showed a similar trend to those of surface energy. A microstructural analysis of CIP/PDMS composites revealed that the CIPs with smaller ΔG values showed a better dispersibility, which is consistent with the theoretical definition of ΔG. Our study proved an evaluation of ΔG allowed to predict the dispersibility of CIPs in PDMS composites.