Browsing by Author "Cheong, Jun Young"

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    Recycling non-food-grade tree gum wastes into nanoporous carbon for sustainable energy harvesting
    (ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND, 2020-02-21) Venkateshaiah, Abhilash; Cheong, Jun Young; Shin, Sung-Ho; Akshaykumar, K. P.; Yun, Tae Gwang; Bae, Jaehyeong; Waclawek, Stanislaw; Černík, Miroslav; Agarwal, Seema; Greiner, Andreas; Padil, Vinod V. T.; Kim, Il-Doo; Varma, Rajender S.
    The disposal of natural wastes has become a global problem and the use of lower-grade gums is very limited owing to their impurities as well as sticky nature. Rather than disposing these wastes, nanoporous carbon (nC) has instead been synthesized by carbonization and exfoliation. The synthesized nC exhibits a substantially high surface area along with abundant micro/mesopores. This desirable and useful nature of nC is well-suited for water-driven effective electrical energy conversion, which enables the fast evaporation of water via a capillary action through nanopores. Under asymmetric wetting in a water container and ambient conditions, the nC-based energy harvesters showed high capability of electricity production and reliable output generation, easily turning on a blue light-emitting diode (2.5 V and 20 mA) using a stored power source. In summary, many energy harvesters can be manufactured for the scale-up of electricity, and the suitability of regenerated carbon nanomaterials for green energy harvesting can contribute toward alleviating chronic environmental issues.
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    Tree Gum-Graphene Oxide Nanocomposite Films as Gas Barriers
    (AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2020-01-01) Venkateshaiah, Abhilash; Cheong, Jun Young; Habel, Christoph; Waclawek, Stanislaw; Lederer, Tomáš; Černík, Miroslav; Kim, Il-Doo; Padil, Vinod V. T.; Agarwal, Seema
    To reduce the dependency on petro-based conventional plastics, research focusing on bioplastics derived from biological origin has gained precedence. Herein, we report an ecofriendly and a facile synthetic route to develop a freestanding nanocomposite film prepared from the combination of nonedible biodegradable tree gum waste and graphene oxide (GO). Three variants of bionanocomposite films such as GO-gum arabic (GA-GO), GO-gum karaya (GK-GO), and GO- kondagogu gum (KG-GO) were fabricated via solution casting of respective gums with GO (0.5% and 1.0%) in an aqueous environment. GO was thoroughly blended within different types of gum matrices via the hydrogen bond interaction and electrostatic attraction, thus forming interconnected homogeneous GO-gum layered structure. Morphological analysis revealed a natural nacre-like structure comprised of gum-intercalated graphene sheets, which was further confirmed by X-ray diffraction studies. The addition of GO further transformed the brittle gum film into a freestanding film with substantial mechanical strength. Furthermore, the layered nanocomposite films demonstrated enhanced oxygen gas barrier property as well as reduced water vapor transmittance. The barrier properties are comparable to the plastics traditionally used in packaging, emphasizing the potential of tree gums nanocomposite films in packaging applications. Such frugally viable gums can be a cost-effective alternative in the development of nanocomposite films that could be readily used for applications in food packaging, pharmaceutical, and various biomedical industries.