Surface roughness and morphology of polypropylene nanospheres: effects of particles size

Abstract

Nanosphere of polypropylene was synthesised under controlled growth condition. Its molecular weight is equivalent to the commercial grade polypropylene. The SEM is conducted in order to inspect the surface morphology. The surface roughness, i.e. surface roughness amplitude parameters R _a (arithmetic average roughness) and root mean square roughness (RMS or R _q) at nanoscale was calculated for nanoparticles by AFM. It is found that the surface profiles depend on particle size and it increases with increasing particle size. The asperity teeth height R _p, valley R _v and RMS R _q of particles were also calculated and it was found that these parameters are particle size depended. The RMS values are found to be 6˙38 to 77˙72 Å as the particle size varies from 40 to 500 nm. The lower RMS values of polymer nanoparticles acknowledge the atomic scale chain folding. The surface roughness variability (R _q/R _a) of nanoparticles are also calculated and found to be above unity, which denotes an irregular spread of surface height.

Keywords:

• POLYPROPYLENE NANOSPHERES
• AFM
• SURFACE ROUGHNESS
• MORPHOLOGY
• SEM