TY - JOUR
T1 - Toward nanomechanical models of liquid-phase exfoliation of layered 2D nanomaterials
T2 - Analysis of a π − peel model
AU - Botto, Lorenzo
PY - 2019
Y1 - 2019
N2 - In liquid-phase exfoliation for the production of 2D nanomaterials fluid forces are used to gently overcome adhesive interlayer forces, leading to single- or few-layer 2D nanomaterials. Predicting accurately the critical fluid shear rate for exfoliation is a crucial challenge. By combining notions of fluid mechanics and fracture mechanics, we analyze a mathematical model of exfoliation, focusing on the π − peel regime in which bending forces are much smaller than the applied hydrodynamic forces. We find that in this regime the shear rate is approximately proportional to the adhesion energy, independent of the bending rigidity of the exfoliated sheet, and inversely proportional to the size a of a (assumed pre-existing) material flaw. The model appears to give values comparable to those obtained in wet ball milling, but to overestimate the shear rate values reported for turbulent exfoliation (by rotor mixing or microfluidization). We suggest that for turbulent exfoliation a “cleavage model” may be more appropriate, as it gives a stronger dependence on a and smaller critical shear rates.
AB - In liquid-phase exfoliation for the production of 2D nanomaterials fluid forces are used to gently overcome adhesive interlayer forces, leading to single- or few-layer 2D nanomaterials. Predicting accurately the critical fluid shear rate for exfoliation is a crucial challenge. By combining notions of fluid mechanics and fracture mechanics, we analyze a mathematical model of exfoliation, focusing on the π − peel regime in which bending forces are much smaller than the applied hydrodynamic forces. We find that in this regime the shear rate is approximately proportional to the adhesion energy, independent of the bending rigidity of the exfoliated sheet, and inversely proportional to the size a of a (assumed pre-existing) material flaw. The model appears to give values comparable to those obtained in wet ball milling, but to overestimate the shear rate values reported for turbulent exfoliation (by rotor mixing or microfluidization). We suggest that for turbulent exfoliation a “cleavage model” may be more appropriate, as it gives a stronger dependence on a and smaller critical shear rates.
KW - fracture
KW - graphene
KW - liquid-phase exfoliation
KW - mechanics
KW - theoretical modeling
UR - http://www.scopus.com/inward/record.url?scp=85076677147&partnerID=8YFLogxK
U2 - 10.3389/fmats.2019.00302
DO - 10.3389/fmats.2019.00302
M3 - Article
AN - SCOPUS:85076677147
SN - 2296-8016
VL - 6
JO - Frontiers in Materials
JF - Frontiers in Materials
M1 - 302
ER -