Piezoelectric ZnO-CNT nanotubes under axial strain and electrical voltage

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 46; pp. 105 - 112
• Main Authors: Zhang, Jin, Wang, Ruijie, Wang, Chengyuan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2012; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of nanoscale materials; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics; Deformation; Elasticity; Carbon nanotubes; Coatings; Interfaces; Tensile stress; Composite materials; Piezoelectric materials; Piezoelectricity; Stress effects; Zinc oxide; Delamination; Nanostructured materials; Analytical solution; Nanocrystal; Nanomaterial synthesis
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2012.09.001

This paper aims to study the mechanical responses of a piezoelectric composite nanotube subject to an axial strain and electrical voltage. The nanotubes are fabricated by coating carbon nanotubes (CNTs) with zinc oxide (ZnO) nanocrystal. The axial buckling of the ZnO-CNTs nanotubes (ZCNTs) is investigated by using a composite Euler beam model accounting for the piezoelectricity of the coating layer. Particular attention is paid to the strengthening effect of the core CNT and the effect of the piezoelectricity of the outer ZnO layer. Pre-buckling analysis is also conducted to study the static deformation prior to the buckling. Analytical solutions are obtained based on the theory of three-dimensional elasticity and piezoelectricity. In particular, a tensile radial stress is achieved at the ZnO-CNT interface, which tends to separate the ZnO layer from core CNT and may generate delamination in composite ZCNTs. The size-dependence and physical basis of such an interface stress is thus discussed in details for ZCNTs. ► Mechanical responses of a ZnO-CNT nanotube with an axial strain and electrical voltage are studied. ► The analytic formulae are obtained to identify the key factors that determine the buckling. ► The physical basis of delamination and the size-dependence of interface stresses are revealed.