Physical Properties of Carbon Nanotube Sheets Dry-Drawn from Tall MWCNT Forests

Highly aligned MWCNT forests can by grown by catalytic CVD process in a dry-spinable highly oriented form which allows to draw CNT sheets and twist spin yarns [1,2]. However the sheet resistance of such transparent CNT sheets with average height of 300 um is quite high: 500-700 Ohm/sq. Motivation of our study is to grow taller forests with optimal interbundle connectivity [3] which may result in lower sheet resistance of CNT sheets and higher optical transparency by optimized control of CCVD conditions. We have succeeded to grow tall CNT forest with h=1 $\mu$m and resulting sheet resistance about 200 Ohm/sq. To find the correlation between properties of CNT forests and CNT sheets we conducted SEM analysis combined with Raman, AFM and small-angle X-ray scattering. This study shows how the number, geometry, and mechanical strength of interconnects between bundles are related to the physical properties of CNT sheets. \\[4pt] [1] M.Zhang, S.Fang et al., Science, V.309 (2005) 1215 \\[0pt] [2] M.Zhang, K.Atkinson, R.Baughman, Science, V.306 (2004) 1358 \\[0pt] [3] A.Kuznetsov, A.Fonseca et al., Adv.Mat., (submitted)