High-Strength and High-Resilience PVA+AgNW/PDMS Co-Continuous Nanocomposite for Reusable Shock Absorbers

Abstract

Abstract A 3D co-continuous polymer nanocomposite with high strength and high recoverability is demonstrated. This nanocomposite used hard-core-soft-matrix design which is suitable for obtaining the optimal strength. Polyvinyl alcohol (PVA) was freeze-dried together with silver nanowires (AgNW) to fabricate a 3D porous structure as hard-core phase, which was then filled with polydimethylsiloxane (PDMS) as soft-matrix phase via vacuum infiltration. The PVA + AgNW nanocomposite served as the hard core, with PDMS as the soft matrix, with this hard core-soft matrix design allowing for a combination of the excellent strength of the nanocomposite and the resilience of the PDMS. The addition of AgNWs strengthened the modulus of the freeze-dried structure over the 3 times and the comparison with the Halpin-Tsai model is indicated of AgNWs were well dispersed into the wall of the 3D structure. The vertical pore alignment of the freeze-dried structure resulted in an increased the strength. In addition, incorporation of hard core-soft matrix significantly increased the strength of the 3D nanocomposite up to 3.5 times that of the PDMS as a result of the co-continuous incorporation of hard and soft phases with well distributed 3D interfaces that also hindered crack propagation. Therefore, the PVA + AgNW 3D porous structure contributed by strengthening and toughening of the entire composite, resulting in increasing energy loss coefficients of nanocomposites, which showed good shock absorbance.