Nanotech - an overview

What is Nanotech?  Field of research concerned with manufacturing on the atomic scale - More precisely the nanoscale (10 -9 ) which is within 1-100 nanometers  The normal rules of physics and chemistry no longer apply - A material’s characteristics can differ significantly between the nano and macro scales  Nanotech can be advantageous because scientists can enhance the properties when engineering a new material by experimenting on the atomic scale Different types of nanotech?  Natural nanomaterials occur naturally in our world i.e. particles that make up volcanic ash, smoke and even some molecules in our body  Man-made nanomaterials occur from processes created by people i.e. exhaust from fossil fuel burning engines and some forms of pollution. Some nanomaterials are accidently created like exhaust, however nanotech for medical purposes is an example of intentional manufacturing Fullerenes and Nanoparticles:  A way to classify nanomaterials is between fullerenes and nanoparticles (this process includes both natural and man-made nanomaterials)  Fullerenes - Allotropes (different molecular forms of the same element) of carbon - Atom-thick sheets of carbon allotrope graphene rolled into spheres or tubes - Most familiar spherical fullerene is the bucky ball (C 60 ) a ‘ball’ of carbons – resembles the shape of a soccer ball - Tubular Fullerenes are called nanotubes (which are remarkably strong and flexible)  Nanoparticles - Include carbon, like fullerenes, as well as nanometre-scale versions of many others elements such as gold, silicon and titanium - Properties have been important in the study of nanomedicine i.e. Use of gold nanoparticles to fight lymphoma (type of blood cancer) Intentionally produced nanomaterials:  Carbon-based- fullerenes: nanotubes, buckyballs  Metal-based – gold nanoparticles and quantum dots  Dendrimers – nanoparticles built from linked branched units containing three sections: a core, an inner shell and an outer shell + branched ends  Nanocomposites – combining nanomaterials with bulk materials or other nanomaterials - Examples include: nanoceramic matrix composites, metal matrix composites and polymer matrix composites Nanotech and the environment:  Energy - Nanotechnology is advancing the development of alternative energy sources, such as solar and wind power  Water - Nanomaterials can aid with the clean water dilemma: They can strip water of toxic metals and organic molecules

Field of research: Carbon based nanotubes and their advantageous properties for wind turbine application “Enhanced Fatigue life of carbon nanotube-reinforced epoxy composites” Article aims to investigate the effect of incorporating small amounts of Multiwalled carbon nanotubes (MWCNT’S) on the fatigue life of a structural epoxy system widely used in wind- energy industries. Experimental: - The epoxy matrix is a modified diglycidyl ether of bisphenol-A with an amine hardener - Physical Properties of the MWCNTs: average diameter of 13nm and length larger than 1 μ m - Dispersing agent of BYK-9077 was used to aid the dispersion (distributed particles of CNT are dispersed in a continuous phase of epoxy matrix) of CNTs in the epoxy system - The samples were prepared in the means centrifugation, filtration and sonication Results + Discussion: Fig 1: Stress-strain curves for neat epoxy (without CNTs) and epoxy/CNTs composites under quasi-static loading – inertial affects are negligible (Horizontal lines mark linear regime limit for each sample) As seen in fig 1, the neat epoxy shows a linear respone up to about 20 MPa, whilst the composites show an extended response up to about 30 MPa. Furthermore, the response of the composites beyond the proportionality limit is considerably more linear than that of the neat material. Therefore, it would be expected that the neat epoxy samples will be prone to plastic de-formation at lower load levels than the composites. Consequentially, fig 1 suggests that at a given stress level, the amount of damage generated in a composite specimen would be probably lower than that created in a neat epoxy, hence suggesting a longer fatigue life.

Fig 4: Variation of nano hardness with elastic modulus of epoxy resin (neat epoxy) and MWCNTs/ epoxy resin composites So, what is my research question? To what extent are multi-walled carbon nanotubes (MWCNTS) suspended in an epoxy matrix a better alternative than neat epoxy engineered wind turbine blades regarding fatigue life, tensile strength and elastic modulus properties?