Facile preparation of graphene-based chitosan films: Enhanced thermal, mechanical and antibacterial properties

Abstract

Chitosan is considered a model polymer because of its excellent biocompatibility, biodegradability, antibacterial property and metal binding ability. Despite the favorable properties, the poor mechanical strength and the loss of structural integrity limits the applications of chitosan. Graphene's intrinsic low weight with excellent thermal stability makes it an ideal filler for reinforcing polymers. In this work, we prepared graphene oxide (GO) via Hummer's method and simplified Hummer's method using graphite powder and graphite flakes as starting materials, respectively. The GO obtained using Hummer's method and simplified Hummer's method had a small area of less than 50 μm 2 and a large area of about 7000 μm 2 , respectively. The small area GO and large area GO were reduced by sodium hydroxide, in which the reduced GO (rGO) with small area and large area were incorporated into a chitosan matrix, respectively, using a simplistic drop-casting technique to produce a thin film. Glass transition temperature (T g ) and mechanical strength of chitosan/large area rGO at concentrations of 0.3, 0.6 and 0.9 wt.% of GO were found to be better than chitosan/small area rGO. We also investigated the T g and mechanical strength between chitosan/small area GO and chitosan/small area rGO, where we discovered that the former had better thermal and tensile properties. By comparing the T g and mechanical strength of chitosan/small area GO against chitosan/large area GO, we found that the latter displayed superior thermal and tensile properties. Antibacterial tests were performed on the graphene-based chitosan composites and their ability to act as bactericide was manifested in the retardation of the growth of Pseudomonas aeruginosa. These composite materials with excellent thermal, tensile and antimicrobial properties find real-life applications in the physical, chemical, mechanical, electrical and bioengineering fields.

Exceedingly biocompatible and thin-layered reduced graphene oxide nanosheets using an eco-friendly mushroom extract strategy

“…The GO sheets had probably crumpled during the exfoliation stage and remained in that position even after reduction. 56 The formation of RGO was further confirmed by XPS analysis. The C1s of GO as shown in Figure 4A demonstrates the highest intensity at the binding energy of 287.8 eV, which belongs to carbonyl functional groups.…”

Graphene Oxide as Antimicrobial Against Two Gram-Positive and Two Gram-Negative Bacteria in Addition to One Fungus

“…GBMs have been tested as antibacterial against food borne pathogens bacteria e.g., E. coli and S. aureus (Santos et al, 2012;Liu et al, 2012;Tang et al, 2013); opportunistic pathogens bacteria e.g., P. aerogenosa and Klebseilla sp. (Lim et al, 2012;Bykkam et al, 2013); plant pathogen e.g., Xanthomonas oryzae and against fungi e.g., C. albicans and C. tropical (Li et al, 2013). Also several studies demonstrated and developed an environment friendly, cost effective, simple method and green approaches for the reduction of GO using microbial cells such as E. coli, Shewanella and Yeast (Gurunathan et al, 2013;Wang et al, 2011;Khanra et al, 2012).…”

Chitosan nanocomposites based on distinct inorganic fillers for biomedical applications

“…They were able to achieve enhanced mechanical performance, but more importantly they have shown that after 24 h a significant delay in Pseudomonas aeruginosa was obtained. [171] Lim et al [172] also explored the ability of rGO and CHI nanocomposites to retard the growth of Pseudomonas aeruginosa . The achieved data revealed that bacterial growth was not dependent on the concentration and size of rGO and could be completely suppressed by the low concentration of rGO in the chitosan solution, leading to a maximum viability loss of 100%.…”