Collapse analysis of nanofibres

Abstract

Continuous nanofibres fabricated by the electrospinning technique have found increasingapplications (e.g. nanofibre composites, nanofibre devices, bioengineering tissue scaffolding,etc). For a nanofibre network subjected to a small external perturbation, the fibresegments within the network may deflect and stick to each other under the conditionthat their surface adhesion energy overcomes the elastic strain energy induced byfibre bending. Therefore, this paper aims to study adhesion-induced nanofibrecollapse and relevant criteria. A simple fibre collapse model was proposed, which isbased on the contact of two deflected elastic filaments under surface adhesion.Four fundamental fibre collapse modes (i.e. fibre-flat substrate, parallel fibres,orthogonal fibres and fibres at arbitrary angle) were considered, and correspondingcollapse criteria were determined in explicit forms. Effects of fibre elasticity, surfaceadhesion and fibre geometries on the collapse criterion were explored in a numericalmanner. Results show that for a fibre segment pair at a relatively large angle, thecritical distance to induce the fibre collapse is independent of the fibre radius. Thisdistance is a function of the fibre aspect ratio and the material intrinsic length(γ/E, whereγ is the surfaceenergy and E is Young’s modulus). The fibre collapse model developed in this study can be used as thetheoretical basis for design and failure analysis of nanofibre networks and nanofibre devices,among others.