Conducting biopolymer-carbon nanotube composite materials for sensing applications

International Conference and Exhibition on Biopolymers & Bioplastics

August 10-12, 2015 San Francisco, USA

Ali Aldalbahi1 and Chunhai Fan1, 2

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

Carbon nanotubes (CNTs) have unique electronic, mechanical, optical and thermal properties which make them interesting as a
material for nanotechnology applications. However, the use of CNTs is limited due to their aggregation behaviour and insolubility
in most common solvents. This poor process-ability is due to high surface energy and the extremely strong π and Van Der Waals
interactions. Many different processing methods for fabrication of conducting CNT materials have been used including filtration,
fiber spinning, inkjet printing and drop casting. Carrageenan is a generic name for the biopolymer family of water soluble, linear
sulphonated galactans extracted from red seaweed which are known for their gel forming and thickening properties. Homogenous
CNT dispersions using Kappa-carrageenan (KC) as dispersant were prepared by sonication. The length of sonication required to
disperse SWNTs and MWNTs in KC was optimized using UV-vis-NIR spectroscopy. Our results indicate that MWNTs require
less sonication time compared to SWNTs, i.e. 20 minutes versus 35 minutes. Rheology results show that increasing the sonication
time reduces the apparent viscosity of KC solutions, while addition of CNT increases viscosity significantly. Free standing films
were prepared by evaporative casting and vacuum filtration processes. The conductivity of MWNT composite films prepared by an
evaporative casting process were similar compared to those of the SWNT composite films (7-9 S/cm). In contrast, the conductivity
values of SWNTs composite films (25 S/cm) prepared by a vacuum filtration process were higher compared to those of the MWNTs
composite films (16 S/cm). Addition of glycerin to these films reduced their conductivity, but increased their flexibility. Scanning
electron microscopy revealed that the difference in conductivity is due to the biopolymer coverage of the CNT-CNT junctions in the
CNT network. This work contributes to the development of conducting biopolymer composite materials.

Biography :

Ali Aldalbahi was born in Afeef, in 1982. He completed his Bachelor degree in Chemistry from King Saud University, Riyadh, Saudi Arabia, in 2004. In 2008, he
completed his master degree in Nanotechnology from University of Wollongong, Australia. He received the PhD degree in material science from the University of
Wollongong, Australia, in 2013. From 2003 to 2013, he was Teaching Assistance, Department of Chemistry, College of science, King Saud University, Riyadh, Saudi
Arabia. Since 2013, he has been Assistant Professor at the same University. He is the author of more than 15 articles in reputed journals. His research interests
include the polymers, composite materials and nanostructured materials, for various types of applications such as gas sensors, humidity sensors, thermal sensors
and water purification. He is members of three scientific associations including Australian Nanotechnology Network (ANN), Saudi Chemical Society (SCS) and
Material Research Society (MRS). He has been committee member for the Master of polymer program and training program at King Saud University.