Hyeonseong Bak

Multiwalled Carbon Nanotubes-Embedded Electrospun Bacterial Cellulose Nanofibers

Multiwalled carbon nanotubes (MWCNTs) were embedded in electrospun bacterial cellulose (BC) nanofibers, which were prepared using an electrospinning method. In this study, Gluconacetobacter xylinum BRC5 was employed to produce a hydrogel-like bacterial cellulose (BC) sheet. BC was difficult to process in the solution stat because of the large concentration of intra- or inter-molecular hydrogen bonds. In this study, an ionic liquid, 1-allyl-3-methyl-imidazolium chloride, was used to dissolve BC. To form BC nanofibers, 5 wt% BC solutions both with and without MWCNTs were electrospun. Scanning electron microscopy and transmission electron microscopy showed that the MWCNTs were embedded and well aligned along the fiber axis. The crystalline polymorph transformed from cellulose I (pristine BC) to cellulose II (electrospun regenerated BC fibers). Moreover, the tensile strength and modulus of the MWCNT-embedded electrospun BC nanofibers increased by approximately 290% and 280%, respectively. Additionally, the thermal stability and electrical conductivity of the MWCNT-embedded electrospun BC nanofibers also increased compared to pristine BC.

Polyaniline/Silver Nanoparticle-Doped Multiwalled Carbon Nanotube Composites

A simple method was used to synthesize the hybrid nanocomposites consisting of the functionalized multiwalled carbon nanotube composites (MWCNTs) with the polyaniline incorporated silver nanoparticles (a-MWCNT/PANI-Ag) through an emulsion polymerization at room temperature in order to enhance the electrical conductivity of polyaniline. The electrical conductivity of the composite with the incorporated Ag nanoparticles was 5% higher than the same weight percent for the composite without Ag nanoparticles, and the thermal stability was dramatically increased from 54% for the composite (a-MWCNT/PANI) to 69% through the incorporation of the Ag nanoparticles at 830°C. Additionally, the advantages of the Ag nanoparticles, including the improved electrical and thermal properties without damage to the polyaniline structure, were confirmed using FTIR and Raman spectroscopy.