Interfacial and mechanical properties of liquid crystalline elastomer nanocomposites with grafted Au nanoparticles: A molecular dynamics study

Abstract

Synthesizing surface-grafted Au nanoparticles (grafted-AuNPs) for incorporation into a liquid crystalline elastomer (LCE) matrix yields high contents of nanoparticles that are chemically compatible and soluble in the matrix. To investigate the change in the internal microstructure by inserting grafted-AuNPs and the mechanical role of the interfaces in the LCE/Au nanocomposites, all-atom molecular dynamics simulations were conducted. The results suggest that the insertion of the grafted-AuNP disrupts the LCE mesogen arrangement, especially in the interfacial area. Additionally, the strain energy density distributed to each molecular component revealed that the grafted unit on the side of the LCE matrix forms a highly entangled network with a semi-rigid microstructure and enables high load transfer efficiency. By contrast, a ductile grafted layer formed on the side of the AuNP surface acts as a cushion, which allows the AuNP to exist in the unloading state. Furthermore, the curvature of the inserted AuNPs is crucial in changing the mechanical and structural properties of the LCE matrix phase.