7th World Nano Conference June 20-21, 2016 Cape Town, South Africa

Honey S. is working as a Graduate Research Student (PhD) at Centre of Excellence in Solid State Physics, University of Punjab, Lahore, Pakistan. She is a fellow of UNESCO UNISA AFRICA Chair in Nanosciences/Nanotechnology and Nanosciences African Network (NANOAFNET), an ICTP network as well. She has published eight papers in reputed journals during her PhD studies.

Interconnection between Ag-NWs is essential for the integration and assembly of NWs networks to enable optoelectronics and nanoelectronics applications. In this report, joining of Ag-NWs through argon ion beam irradiation technology is demonstrated. A range of experimental traits of constructing X-, and II-shapes molecular junctions between Ag nanowires and the utilization of the argon ion beam irradiation induced nanowelding technique to form functional metal NWs networks is conferred. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy results revealed that Ag-NWs are effectively connected to each other on intersecting positions and crystal structure also remained un-damaged. Besides, technical hindrances facing the ion irradiation induced nanowelding technology are also discussed. A perspective is given for using argon ion irradiation induced welding technique for the construction of random networks of well-connected nanowires.

Steve Lenk, Dipl.-Ing. is project coordinator assistant of the European FP7 project “Single Nanometer Manufacturing beyond CMOS devices” (SNM). He graduated at the Faculty of Technical Physics at Technische Universität Ilmenau, specialties Theoretical Physics and Semiconductor Physics, in 2009. In his Diploma thesis he calculated the excitonic dielectric function of GaN. He works currently at his PhD with the topic simulations of the Fowler-Nordheim emission of electrons from ultrasharp nanotips for lithography. He has experience in scientific programming, analytical solutions, and EU projects management. He has 3 publications in scientific journals.

The scanning probe lithography (SPL) is based on the F-N-field-electron emission from a SPM- nanotip and an exposure of a calixarene resist. Since the emitted electron energies are in the range of a few ten electron volts, i.e., in the range of the binding energies of the resist molecules, they are chemically triggered and converted into volatile compounds. The field emission is enhanced due to the geometry of the nanotip (lightning rod effect). Until now, the mechanisms and conditions behind the physical processes are not clearly understood. Therefore, we simulate the emission process using a 2D and 3D model. The 2D method consists of the computation of the emission probability at the tip excluding the original electron energy and of the electron trajectories using a Velocity-Verlet algorithm. Our 3D model additionally includes the electron energy distribution inside the tip and the 3D geometry of an axial symmetric tip. Thus, we are able to calculate a realistic electron energy distribution at the surface with our 3D model. We will compare the two models with experimental Fowler-Nordheim data to show the dependence of the electron density and the energy distribution of the electrons. Additionally, we will present the electric field and electron distribution influenced by the resist material.

Letitia Burgess is a second year PhD student funded by the Biotechnology and Biological Sciences Research Council Doctoral Training Partnership (BBSRC DTP) at the University of Manchester. She also completed her undergraduate and Master’s degree at the University of Manchester. She also undertook a 3 month placement at C4X discovery, a drug discovery company that specialises in NMR conformational analysis to optimise the design and development of medicines.

Current biological imaging methods utilize organic dyes and quantum dots as contrast agents, however they suffer from problems such as autofluorescence of the biological tissues and toxicity, which limit their effectiveness in vivo. Upconverting nanophosphors have emerged as a new class of compounds for use in biological tissue imaging, as they do not suffer from the same limitations as current techniques due to their chemical stability and excitation using near infrared light, a region in which biological samples are silent and a wavelength capable of penetrating deeper into the tissue. Enzymes have a high selectivity/specificity and are capable of detecting their substrates at sub nanomolar concentrations. Examples exist in the literature of biosensing platforms for the detection of substrates using upconverting nanophsophors electrostatically interacting with enzymes, antibodies and other biomolecules. It is proposed that covalently attaching the enzyme to the surface of the nanoparticles could increase this interaction and improve the sensitivity of these systems. However to date there is little understanding of the surfaces of the nanoparticles and no bio-toolbox exists for the covalent attachment of enzymes to upconverting nanophosphor surfaces. This project aims to develop the understanding necessary and the methods needed for covalent attachment of enzymes to upconverting nanophosphor surfaces in order to create biosensing platforms for the detection of enzyme substrates at low concentrations.

Lukhwa Rendani, age 27 has completed honors in physical science at the university of the western cape and currently doing his master of science in the same institution. He has been awarded the scarce skill scholarship by nrf since the beginning of his MSc.

This contribution reports on the structural, optical and morphological of nanostructured flexible solar-thermal selective absorber composites for low temperature applications. The candidate material in the system is consisting of electrodeposited nickel nano-cylinders embedded in track-etched polyethylene terephthalate host membrane of pore sizes ranging between 0.3-0.8µm supported by conductive nickel thin film of about 0.5µm. The tubular and metallic structure of the nickel nano-cylinders within the insulator polymeric host forms a typical ceramic-metal nano-composite “Cermet”. The produced material were be characterized by the following characterization techniques: X-ray diffraction(XRD) for structural characterization to determine preferred orientation, crystallographic structure, and grain size of the materials; Scanning electron microscopy(SEM) to determine surface morphology, particle size, and visual imaging of distribution of structures on the surface of the substrate; Atomic force microscopy(AFM) to characterize surface roughness, surface morphology, and film thickness, and UV-vis-NIR spectrophotometer to measure the reflectance, then to determine solar absorption.

Enas Ismail is a PhD student at Collegue of Science, Engineering and Technology, university of South Africa. She is also an Assistant lecturer in the Faculty of Science "Girls branch", Al Azher University, Egypt. She is a fellow in the UNESCO UNISA Africa Chair in nanoscience and nanotechnology. She obtained her master degree (M. Sc.) as well as B.Sc. in the Biophysics, specialist in material science from Al-Azhar University at 2011 and 2006 respectively. She is interesting about nano-materials, bio-materials, nano-biotechnology, green chemistry and biologican and medical applictions. She has published a round 8 papers in an international journals.

This contribution report on the bio-synthesis of Rhodium metallic nanoparticles (Rh NPs) synthesized for the 1st time by a completely green process using Aspalathus linearis natural plant extract as an effective bio-oxidizing/bio-reducing agent as well as a capping compound. Their morphological, structural and optical properties were investigated using various complementary surface/interface characterization techniques such as HR-TEM, HR-SEM, EDS, XRD, XPS and UV spectroscopy. The results confirm the formation of quais - monodisperse spherical Rh NPs in the range of 0.8-1.6 nm.

Mouafo Teifouet Armand Robinson has completed his Msc from University of Dschang, Cameroon and he is currently doing his PhD at the University of Kwazulu-Natal in South Africa under supervision of Professor SARP Adali. He has published 3 papers in reputed journals and has submitted two others.

The rapid increase of the nanostructure’s devices manufacturing requires a careful study of carbon nanotubes (CNT) behavior undergoing buckling, in order to optimize the design of such devices. The aim of the present paper focuses on the study of buckling of the elastically restrained CNTs subjected to concentrated and uniformly distributed loads. That structure is mathematically modelled as nonlocal Euler-Bernoulli beams. Weak formulation of the obtained governing equation is derived and we employ the Chebyshev polynomials-based Rayleigh-Ritz method to solve the eigenvalue equation. By taking particular values of rotational and translational spring constants, boundary conditions are derived and the present obtained buckling load are compared to those existing with good satisfaction. Contour plots show the effect of both nonlocal parameter and spring constants on the behavior of buckling loads. The main observation is that, it depends on the nature (rotational or translational) and values of the spring constants.

Ms. Angela KARORO, originally from Uganda is a carrying out her PhD studies in selective solar absorbers for Concentrated Solar Power at the University of South Africa under the framework of the UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology. She is an awardee of the German Academic Exchange Service and the Joint-US Africa Materials Institute as well as the African Laser Centre.

This work reports on the structural and optical properties of laser surface structured Co nano cylinders-Al2O3 cermets for enhanced solar selective absorbers applications. The electro deposition of the Co nano cylinders into the porous alumina arrays is a suitable technique to produce nano materials, since highly ordered uniform nano materials can be obtained simply and in a cost effective way. A femtosecond fiber laser pulsing at the fundamental wavelength of 1064 nm was used to surface structure the thin film Co-Al2O3 composites. The structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy; their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance() above 98% and an emitance() ~0.03 in the spectral range of 200-1100nm which make them potential candidates as mid-temperature selective solar absorbers. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasm on surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring.

Hamza Mohamed, 26 years old is pursing MSc studies in Physics with the University South Africa. He is the recipient of the award from the African Institute for Mathematical Sciences – South Africa, (AIMS-SA), and the Post Graduate Support Grants (Top- Up). His current research is focused on studying the morphological structures, and synthesize nanoscaled metallic oxides using Green process.

Nowadays, the development of efficient green chemistry methods for synthesis of metal oxides nanoparticles has become a major focus of researchers. They have investigated in order to find an eco-friendly technique for production of well-characterized nanoparticles. Green synthesis of nanoparticles is an eco-friendly approach which might provide the way for researchers all over the world to explore the potential of different herbs in order to synthesize nanoparticles. In this contribution, reports on the synthesis and the main physical properties of n-type Bismuth vanadate (BiVO4) nanoparticles for the first time by a completely green process using aqueous extracts of Callistemon viminalis as a chelating agent, Bi nitrate and Na orthovanadate salts. To ascertain the formation of BiVO4 if at all, XRD, SEM and HRTEM have been done.

Ruqsar Bibi Ismail obtained her Bachelor of Science with Majors in Genetics and Microbiology from the University of KwaZulu-Natal in 2013 and in 2014 pursued further a Bsc (Honours) degree in Microbiology and won best student presentation at the 27th annual South African Society for Microbiology-KZN Symposium. Ms Ismail is currently a Masters student in the School of Life Sciences at the University of KwaZulu-Natal (Westville) and has shown interest in green biotechnology and sustainable development.

The development of techniques for the synthesis of nanoparticles of well-defined size, shape and composition is a challenge and an important area of research in nanotechnology. Many microorganisms have the ability to produce inorganic nanostructures and metal nanoparticles with properties similar to chemically synthesized materials and are a good alternative approach to chemical synthesis. In the present study, extracellular synthesis of gold nanoparticles (AuNPs) in the presence of fungal extracts has been successfully demonstrated to manipulate the size and shape of gold nanoparticles by alteration of key growth parameters (Temperature, pH, incubation period, and sodium citrate concentrations) and reaction conditions (Supernatant: HAuCl4). Production of nanoparticles was confirmed by the colour change from yellow to violet-blue after ~72h of reaction. The synthesis of the AuNPs was monitored by UV-visible spectroscopy which showed an absorbance peak at ~530 nm which was specific for gold nanoparticles. The particles thereby attained were characterized by Transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) and energy dispersive X-ray (EDX) analysis. TEM images revealed that the nanoparticles were spherical, triangular, rod-shaped, polygonal and irregularly shaped with indefinite morphology in the range of 3-460 nm in size. The most promising results were obtained when the fungus was grown at pH 3, 40º C and the best parameters for the synthesis of gold nanoparticles were pH 3, 32 ºC, 40h, 5mM sodium citrate concentrations and ratio of 1:100. The GNPSs were monodisperse, spherical and found to be 3-53 nm in size. FTIR absorption spectrum showed the presence of bonds due to O-H stretching (around ~3,430 cm -1). This peak indicates the presence of proteins and other organic residues, which might have been produced extracellularly during the growth of the fungus. An elemental composition analysis employing EDX showed the presence of a strong signal from gold atoms. However, there were other EDX peaks for C, O, Cr, Cu and Fe, suggesting that they were mixed precipitates from the fungal extracts and the copper disks. This study represents an important advancement in the use of of fungal enzymes for the biosynthesis of highly stable gold nanoparticles by a greener approach and this proposed mechanistic principal might serve as a set strategy for the synthesis of nanostructures with desired morphology and can be amenable for large scale commercial production and technical applications.

Takalani Nethavhanani has completed her BSc from the University of Venda and obtained her BSc. (Hons) from the University of the Western Cape in 2015. She is currently doing her second year MSc. at iThemba LABS- a group of multi-disciplinary research laboratories based in the Western Cape unde the supervision of Prof. Malik Maaza.

ZnO is a wide band-gap semiconductor “~3.7 eV” at room temperature with a wurtzite crystal structure. It has attracted a significant interest worldwide as the ideal candidate for blue-UV light emitting diodes applications. Its multifunctionality as a transparent conducting oxide, effective piezoelectric, a selective gas sensor and an efficient catalyst support among others, has made it as one of the most studied simple oxide in its nano form in the modern era. Nano-scaled ZnO has been synthesized in a plethora of shapes. A rich variety of physical and chemical methodologies were used to synthesize undoped or doped ZnO. The synthesis of ZnO nanoparticles by conventional physical and chemical methods has been reported to have adverse effects such as critical conditions of temperature and pressure, expensive chemicals, long reflux time of reaction and toxic by-products. The green synthesis approaches which are based on using biogenic processes, whereby the precursor of the nano-material to be synthesized, is reduced or oxidized effectively via a biochemical interaction with the active compounds of the natural system, is gaining a worldwide interest. Plants’ natural extracts mediated biosynthesis are used to produce a variety of oxide nanoparticles as well as metallic nanoparticles. This work reports on the synthesis and the main physical properties of ZnO nanoparticles synthesized by a completely green process using Aspalathus Linearis’s natural extract as an efficient chelating agent. The structural and thermal properties were investigated by X-ray Diffraction, Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Thermal Gravimetric Analysis and Differential Scanning Calorimetry.

Mrs Touria Khamliche, a native of Morocco/North Africa hold a BSC (hons) in physics from Mohammed V University-Agdal Rabat, Morocco and a degree in Engineering Technology (Computer System, Networking and Telecommunications) from National School of Applied Sciences of Tangier (ENSAT), Morocco. She is pursing Master studies in Physics at the University South (UNISA).

A nanofluid with developed and advanced high temperature heat transfer is crucial for the enhancement of concentrated solar power (CSP) efficiency, and consequently, the cost reduction of electricity production [1]. Incorporation of metallic nanoparticles into heat transfer fluids used in CSP application could result in nanofluids with improved thermal transport properties [2]. This study reports on the synthesis and investigation of silver nanowires (AgNWRs) based nanofluids synthesized by the polyol process in ethylene glycol (EG) as a reductant, polyvinylpyrrolidone (PVP) as structure-directing agent for the growth of Ag nanowires. Structural and morphological characterisations revealed highly crystalline three-dimensional (3D) interconnected network of Ag nanowires. EG-based suspensions in the presence of various AgNWRs loadings (0.5–2 vol.%) were prepared and thermal conductivity measurements were conducted. A thermal conductivity enhancements over the EG base fluid of 30% at a 2 vol.% AgNWRs loading was achieved.

Z. kweyama is MSc fellow from University of Zululand under the National Research Foundation (NRF)/MANUS/MATSCI program. She is doing her research under the NRF/iThemba LABS Material Research Department. Her research interest is in material science, synthesis and characterization of nanomaterials. Dr N. Thovhogi is a Research fellow under UNESCO UNISA African Chair in Nanosciences & Nanotechnology and iThemba LABS, with expertise in green synthesis or biosynthesis of various nanomaterials. Dr B. Kibirige from University of Zululand is an expert in Material Sciences and she is a fellow in South African Institute of Physics. Prof. M. Maaza holds the UNESCO UNISA African Chair in Nanosciences & Nanotechnology.He is an expert in nanophotonics and materials at nanoscale.

This contribution reports on the synthesis and the main physical properties of Cerium oxide (CeO2) nanoparticles synthesized by a completely green chemistry process using hibiscus sabdariffa flower natural extract as an effective chelating agent. The biosynthesized CeO2 nanoparticles were found to be as small as 3.9 nm in diameter. Their morphological, structural and optical properties of such nanoparticles were analyzed by High resolution Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Electron Dispersive X-rays Spectroscopy (EDS), X-Rays Diffraction (XRD), Infrared (ATR-FTIR), Raman and X-Rays Photoelectron Spectroscopy(XPS).

Badejo, O A his currently a PhD researcher at Department of Chemical Science, Faculty of Science, Olabisi Onabanjo University, Nigeria. A Chief Lecturer at Adeniran Ogunsanya College Of Education, Lagos. Nigeria. He has published more than 25 papers in refared journals.Lawal, S.O his a Professor of Industrial Chemistry at Department of Chemical Science, Faculty of Science, Olabisi Onabanjo University, Ogun State, Nigeria. He has published several papers in reputed journals.Alabi-Abass M.O her currently a M.Sc student at Department of Chemical Science, Faculty of Science, Olabisi Onabanjo University, Ogun State, Nigeria.

Cellulose represents a new emerging biological resource of great industrial and environmental importance. The current trend of isolation of cellulose from agricultural wastes has contributed to a very large extent, in combating environmental problems such as pollution and threat to food security across the globe. Isolation of cellulose from Hura Crepitans seed pod (sand box) was by alkaline hydrolysis using an unbranded locally fabricated steel vessel, with detachable electrically controlled stirrer. Chemical modification of the cellulose was by acetylation under varying conditions of temperature and pH respectively. Degrees of acetylation were determined, and swelling capacities in relation to pH and temperature variations respectively. Fourier transfer infrared (FTIR) spectra showed that groups of the native cellulose were partially substituted by acetyl groups. Determinations of degree of acetylation and swellings capacities showed that modification occurred. Further investigation revealed that acetylation and swelling capacities increased with increase in pH and temperature respectively. It was recommended among others that isolation of cellulose from sand box is a new resource for industries and not a waste as usually termed.

Christopher has completed his honours degree in microbiology at the age of 2 years from university of Venda and now is doing his 2nd year MSc in nanoscience at University of the Western Cape. He has co-authoured in an article titled “ Identification and characterization of a heat-inducible Hsp70 gene from Sorghum bicolor which confers tolerance to thermal stress”.

The synthesis of metal nanoparticles using marine algae has largely been unexplored, but it is regarded as a more greatly biocompatible method than other methods. The synthesis of gold nanoparticles using the green seaweed Ulva lactuca algae aqueous extract shows a rapid and non-toxic process which resulted in nanoparticles which have the greatest potential for biomedical applications owing to their water solubility. In this investigation, we studied the green synthesis and characterization of gold nanoparticles using the live Ulva lactuca marine organism. The formation of gold nanoparticles was preliminary observed with the change of colour from a yellow to dark pink colour characteristic of gold nanoparticles which was confirmed by the observation of the surface plasmon resonance band at 530 nm using UV–visible spectroscopy. The synthesized nanoparticles were further characterized using transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS). The simple process for the biosynthesis of gold nanoparticles is rapid, cost-effective and eco-friendly and the study further eliminates the use of additional chemicals as reducing and stabilizing agent. Nanoparticles synthesized through such environmentally benign routes can be used for synthesizing many other metal nanoparticles as well as for a wide range of biomedical applications, for commercial production on a large scale and also can be used as efficient catalysts for different organic reactions.