Heyi Liang, Zhen Cao, Andrey V. Dobrynin*
Macromolecules 2016, 49 (18), 7108–7115
Abstract:
We use molecular dynamics simulations to study mechanical properties of polymeric nanocomposites of liquid inclusions in polymeric network matrix. The shear modulus of nanocomposite is shown to be a universal function of the elastocapillary number γNL/(GNR0), where γNL is the surface tension of the liquid/network interface, GN is the shear modulus of the network and R0 is the initial size of liquid inclusions. First, in the range of elastocapillary numbers, γNL/(GNR0) < 1, the composite shear modulus increases with increasing elastocapillary number. In this interval of elastocapillary numbers, liquid inclusions soften the network such that the composite modulus GC is smaller than GN. However, for elastocapillary numbers γNL/(GNR0) ≈ 2, the liquid inclusions begin to reinforce the network resulting in GC > GN. In such composites, the surface energy of the deformed liquid inclusions stiffens the composite. When the elastocapillary number increases further, γNL/(GNR0) ≫ 1, the interfacial energy of network/liquid interface dominates the mechanical response of the composite. Elongation ratio of the liquid inclusions monotonically decreases with increasing elastocapillary number γNL/(GNR0).
URL:
https://pubs.acs.org/doi/10.1021/acs.macromol.6b01499
* Corresponding Author