Supplementary material from "A nanoscale perspective on the effects of transverse microprestress on drying creep of nanoporous solids"
Posted on 2017-12-13 - 10:50
The Pickett effect describes the excess non-additive strain developed during drying of a nanoporous solid material under creep. One explanation for its origins, developed using micromechanical models, is the progressive relaxation of internally developed microprestress. However, these models have not explicitly considered the effects of this microprestress on nanoscale energy barriers that govern the relative motion and displacement between nanopore walls during deformation. Here, extending previous studies not accounting for this microprestress, we evaluate the nanoscale effects of transverse microprestresses on the drying creep behaviour of a nanoscale slit pore using coarse-grained molecular dynamics. We find that the underlying energy barrier depends exponentially on the transverse microprestress, which is attributed to the changes in the effective viscosity and degree nanoconfinement of molecules in the water interlayer. Specifically, as the transverse microprestress is relaxed (i.e. its magnitude is decreasing), the activation energy barrier is reduced, thereby leading to an acceleration of the creep behaviour and a stronger Pickett effect. Based on our simulation results, we introduce a new microprestress-dependent energy term into our existing Arrhenius model, which describes the relative displacement of pore walls as a function of the underlying activation energy barriers. Our findings further verify the existing micromechanical theories for the origin of the Pickett effect and establish a quantitative relationship between the transverse microprestress and the intensity of the Pickett effect.
CITE THIS COLLECTION
Sinko, Robert; Bažant, Zdeněk P.; Keten, Sinan (2017). Supplementary material from "A nanoscale perspective on the effects of transverse microprestress on drying creep of nanoporous solids". The Royal Society. Collection. https://doi.org/10.6084/m9.figshare.c.3952945.v1
Select your citation style and then place your mouse over the citation text to select it.
Read the peer-reviewed publication
Zdeněk P. Bažant