Optical and Structural Properties of Solvent Free Synthesized Starch/Chitosan-ZnO Nanocomposites

Abstract

The objective of this work is to develop an environmentally friendly method for preparation of ZnO nanocomposites. ZnO nanocomposites were prepared by three natural fibers such as coir, sawdust, and chitosan using aqueous solution of zinc chloride and sodium hydroxide. The functional groups of ZnO, C=O for polysaccharide, and N-H bending vibration of amine were confirmed by FTIR spectroscopy. A new high intensity absorption band has been observed at 424 cm −1 which corresponds to the E 2 mode of hexagonal ZnO. The crystallinity and phase formation of coir, chitosan, and sawdust combined ZnO nanocomposites were confirmed by X-ray diffraction patterns. XRD patterns revealed the polycrystalline nature of ZnO composites belonging to the hexagonal phase with (101) preferential lattice orientation. The microstructural parameters were calculated for coir, chitosan, and saw wood combined ZnO composites. Also texture coefficients were estimated for all the diffraction lines of ZnO based nanocomposites. SEM and TEM analyses confirmed evenly distributed nanosized grains in the ZnO composites. The UV-Vis absorption spectra were observed where the blue shift absorption peak was at 334 nm. The optical band gap values were estimated in the range of 3.18-3.26 eV. The emission peak was observed at ∼388 nm and ∼463 nm by photoluminescence spectroscopy.

One-Pot Facile Methodology to Synthesize Chitosan-ZnO-Graphene Oxide Hybrid Composites for Better Dye Adsorption and Antibacterial Activity

“…In addition, the CS peak vanished due to the higher crystalline properties of ZnO. Furthermore, we estimated the crystallite size of the nanocomposites using Debye-Scherer’s formula to help deduce their microstructural characteristics [ 56 , 57 ]. Consequently, the crystallite sizes for the CS–ZnO and CS–ZnO–GO hybrids were estimated as 23.2 and 19.5 nm, respectively.…”

Evaluation of the Corrosion Resistance Properties of Electroplated Chitosan-Zn1−xCuxO Composite Thin Films

“…Chitosan is an important natural polymer for various applications including biomedical sensors, implants, and anti-microbial and microfluidic devices [ 12 , 18 , 19 , 20 ]. Nanocomposite materials based on chitosan with metal oxide materials have become attractive in recent years due to their synergistic behavior [ 21 ]. Recently, Sanmugam et al [ 21 ] successfully demonstrated the solvent free synthesis of chitosan-zinc oxide (ZnO) nanocomposites using chitosan and ZnCl 2 .…”

Enhanced Red Emission in Ultrasound‐Assisted Sol‐Gel Derived ZnO/PMMA Nanocomposite

“…Visible emission is widely observed on ZnO nanostructures and has been assigned to the recombinations of photoexcited electrons-holes being trapped at defect states including oxygen vacancies (V O ), zinc interstitials (I Zn ), zinc vacancies (V Zn ), and their complexes [2,6,14,16,17,20,[29][30][31]. Here, we put forward a plausible mechanism shown in Figure 5 to explain PL properties of the ZnO-PMMA composite.…”

“…Incorporation of ZnO into polymer matrix is a convenient way to stabilize the PL properties of ZnO and to add new functionalities to the polymer [6,13,19]. Herein, we observed unexpectedly that poly(methyl methacrylate) (PMMA) matrix quenches the original green-orange emission but enhances red emission of ZnO NPs.…”

“…Zinc oxide (ZnO) is a n-type semiconducting material with a great application potential as electron conduit in (opto) electronic devices [1,2], photocatalysts [3,4], and photoluminescence materials [5,6]. ere are several methods for the synthesis of ZnO nanostructures, including sol-gel method, controlled precipitation, solvothermal techniques, microemulsion, and sonochemical treatments [7].…”