Paper: Long Lifetime, Superhydrophobic, Free-standing Carbon Infiltrated Vertically Aligned Carbon Nanotube Structures

Karlheinz Strobl(a) and Fahd Rajab(b)(c)
(a)CVD Equipment Corporation, 355 S. Technology Drive, Central Islip, NY 11722, USA
(b)Chemical Engineering Department, College of Engineering, Najran University, Saudi Arabia
(c)Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box: 1988, Najran 11001, Saudi Arabia.

Corresponding author: fmrajab@nu.edu.sacreate new email; fahdrajab1@gmail.comcreate new email, Tel: +966175428942

Abstract

Long lifetime, free-standing, superhydrophobic, carbon infiltrated vertically aligned carbon nanotube structures (ct-VACNT) are prepared by VLS assisted VACNT growth on photolithographic patterned catalyst wafers, followed by a carbon infiltration process creating c-VACNT precursor structures (made from a nanoporous carbon sponge material) which are subsequently released from the catalyst wafers, surface roughened on their top and bottom surface and then conformally overcoated with a few nm thick hydrophobic thin film of a hydrophobic amorphous fluoropolymer, thus resulting in free-standing superhydrophobic ct-VACNT structures. Longevity testing of the hydrophobic overcoating shows that the addition of a customized surface roughening step (especially in the form of low-pressure O2 plasma-assisted surface burning of the nanocarbon sponge material) for the bottom and top surfaces is key to extending the hydrophobic lifetime of such ct-VACNT structures from a few weeks to over a year.
These long lifetime ct-VACNT structures can now be used to develop novel fluid processing devices for a range of industrial and medical fluid processing applications requiring gas transfer into and/or out of aqueous liquids. Such novel fluid reactor devices are enabled by application-specific optimized components made from these novel nano-to macro ct-VACNT structures, for example in the form of Fluid channel Array Bricks (FABs).

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