Surface effect on size dependent Young's modulus of nanowires: Exponentially decreased surface elasticity model

Physical and mechanical properties of nanowires are strongly affected by surface effects. In this letter, a continuum theoretical scheme for describing the elastic property of nanowires was proposed. The influence of surface elasticity was considered as a decreasing regular pattern with increasing distance from surface. The decrease law was considered as exponential in this letter. An imaginary interface (between bulk like core and surface area) of nanowires appears in core-surface and core-shell models. This theoretical model avoided the non-physical interface between bulk like core and surface area of nanowires. The larger exponential decrease factor weakened surface effect obviously and was reflected in the effective Young's modulus expression. Due to the influence of descending surface elasticity, the second, third, fourth and fifth surface modifications were introduced. This letter is aim to establish a continuum theory for elastic property of nanowires without any sudden change (interface) of Young's modulus.