Microwave plasma treatment of single wall carbon nanotube (SWNT) films called bucky papers(BPs) resulted in changes in the relative proportion of different chiralities of SWNTs present in theBP and the production of vertical microstructures on the surface of BP. The plasma was createdusing H2 gas mixed with Ar or CH4, at a temperature of 900 �C and a pressure of 70 Torr. Radialbreathing mode spectra of the BPs revealed that the preferential sputtering by plasma is not withrespect to the diameter or the metallic nature of SWNTs. We propose that the lengths of SWNTsinfluence how they interact with plasma. Longer tubes will have higher dielectric constants andhence will be polarized more strongly by the electric field of the plasma sheath. This in turn resultsin greater ion bombardment and sputtering. Finite element method was used to find the strengths ofthe induced electric fields on model SWNT surfaces. Microscopy, Raman, and X-ray photoelectronspectroscopy were used to study the effect of plasma on the crystallinity of the surviving SWNTs.Structural integrity of SWNTs was preserved after the plasma treatment.