Synthesis of three-dimensional hierarchical CuO flower-like architecture and its photocatalytic activity for rhodamine b degradation

The flower-like CuO materials with a good uniformity were successfully synthesized by the self-assembly method. By using pH ranging from 7 to 9, CuO provided different morphologies. X-ray diffraction ̣(XRD) and Scanning electron microscopy (SEM) revealed the purity and uniformity of the CuO particles, respectively. The particles show flower-like structures composed of CuO nano-sheets. Transmission electron microscopy (TEM) confirmed the uniformity of nanosheet-like CuO particles with lattice dimensions of 0.2–0.4 nm. In a preliminary experiment, the rhodamine b degradation was observed by using CuO as a photocatalyst. These semiconducting particles were found to enhance the degradation of the azo dye within 240 min. It was remarkable to note that as-synthesized CuO particles from the self-assembly method provided a good uniformity in morphology. It also exhibited good and suitable properties to serve as a photocatalyst for rhodamine b degradation. Keywords: CuO, Self-assembly, Photocatalyst, Rhodamine

Bacterial cellulose : a smart biomaterial with diverse applications

Natural biomaterials have benefited the human civilisation for millennia. However, in recent years, designing of natural materials for a wide range of applications have become a focus of attention, spearheaded by sustainability. With advances in materials science, new ways of manufacturing, processing, and functionalising biomaterials for structural specificity has become feasible. Our review is focused on bacterial cellulose (BC), an exceptionally versatile natural biomaterial. BC is a unique nanofibrillar biomaterial extruded by microscopic single- cell bacterial factories utilising the chemical energy harvested from renewable substrates. BC is extracellular and is intrinsically pure, unlike other biopolymers that require extraction and purification. BC fibres are 100 times thinner than plant-derived cellulose and exist in a highly porous three-dimensional network that is highly biocompatible. Macro fibres fabricated from BC nanofibrils are stronger and stiffer, have high tensile strength values and can be used as substitutes for fossil fuel-derived synthetic fibres. The increased surface area to volume ratio allows stronger interactions with the components of composites that are derived from BC. The reactive hydroxyl groups on BC allows various chemical modifications for the development of functionalised BC with a plethora of ‘smart’ applications. In this review we consolidate the current knowledge on the production and properties of BC and BC composites, and highlight the very recent advancements in bulk applications, including food, paper, packaging, superabsorbent polymers and the bio-concrete industries. The process simplicity of BC production has the potential for large scale low-cost applications in bioremediation. Furthermore, the emerging high value applications of BC will be in electrochemical energy storage devices as a battery separator, and in transparent display technologies will be explored. Finally, the extensive biomedical applications of BC are discussed including, wound healing, controlled drug delivery, cancer treatment, cell culture and artificial blood vessels. In a further development on this, additive manufacturing considers enhancing the capabilities for manufacturing complex scaffolds for biomedical applications. An outlook on the future directions of BC in these and other innovative areas is presented