Dependence of the mechanical properties of nanohoneycomb structures on porosity

Mechanical properties of nanohoneycomb structures are measured for varying porosity ( or pore diameter) of the nanohoneycomb structure. The indentation modulus and hardness in the pore direction ( or thickness direction) are obtained from indentation tests using a nano-indenter. The bending modulus of the nanohoneycomb structures in the vertical direction relative to the pore ( generally along the beam length) is determined from bending tests in AFM. To determine the bending modulus of the nanohoneycomb structures, the area moment of inertia of the nanohoneycomb structure is determined according to the arrangement of the pores. The indentation moduli and the hardness are found to decrease nonlinearly with increasing porosity. The bending moduli of the nanohoneycomb structures also decrease nonlinearly as a function of porosity over a large range. It is made clear that the elastic modulus of a homogenous material can be controlled by changing the pore diameter.