NANOMATERIALS Seminar: 2013 ACKNOWLEDGEMENT I wish to express my sincere and respectful gratitude to Sri.J.MAHENDRAN NAIR, Chairman of PKCET for providing all our needs during the course of this seminar. I wish to express my deep sense of gratitude to Prof: S. CHIDAMBARAM, the Principal and Head Of Department of Mechanical Engineering Department of PKCET for his constant support and guidance. My deepest thanks to our respected Director of academics, Dr. A.KOMALAVALLI AMMA for her encouragement and support. It would be unfair not to mention about the valuable assistance from our registrar Mr.G.MOHANAN NAIR. I express my sincere gratitude to our seminar coordinator Mr. AKHIL SASI, for his valuable suggestions without which the successful completion of this seminar would not have been possible. I am grateful to Mr. AKHIL SASI, Guide of my seminar, who has contributed both directly and indirectly throughout the completion of the seminar. Dept: Of Mechanical Eng 1 PKCET, Kandala
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NANOMATERIALS Seminar: 2013
ACKNOWLEDGEMENT
I wish to express my sincere and respectful gratitude to Sri.J.MAHENDRAN NAIR,
Chairman of PKCET for providing all our needs during the course of this seminar.
I wish to express my deep sense of gratitude to Prof: S. CHIDAMBARAM, the
Principal and Head Of Department of Mechanical Engineering Department of PKCET
for his constant support and guidance.
My deepest thanks to our respected Director of academics, Dr. A.KOMALAVALLI
AMMA for her encouragement and support. It would be unfair not to mention about the
valuable assistance from our registrar Mr.G.MOHANAN NAIR.
I express my sincere gratitude to our seminar coordinator Mr. AKHIL SASI, for his
valuable suggestions without which the successful completion of this seminar would
not have been possible.
I am grateful to Mr. AKHIL SASI, Guide of my seminar, who has contributed both
directly and indirectly throughout the completion of the seminar.
I wish to thank all the teachers and friends of PKCET, who helped me for making this
seminar successful. Also I wish to express my deep sense of gratitude to my family
members for their constant encouragement and support throughout my academic
carrier.
Last, but not the least, I am grateful to the almighty for guarding and keeping me safe
from any and all misfortunes befalling on me.
Dept: Of Mechanical Eng 1 PKCET, Kandala
NANOMATERIALS Seminar: 2013
AKHIL KUMAR S
ABSTRACT
Nanotechnology and molecular manufacturing allows for manipulation of
material size and composition. This expands the promise of application of
nanomaterials in addressing environmental problems, but also has the
potential for adversely impacting the natural environment and human
health. The primary focus is to use nanomaterials for environmental
remediation and to study the impact of the release of such materials in the
environment. The first part of this talk will focus on the aggregation
behavior of carbon nanotubes (CNTs) in environmentally relevant solution
chemistries. The MWNTs were thoroughly characterized using Raman
scattering (for state of defect), total gravimetric analysis (for metal
impurities), transmission electron microscopy(for length and diameter
groups), and electrophoretic mobility (for surface charge). The aggregation
kinetics of MWNTs was consistent with classical DLVO theory of
colloidal stability in presence of Na, Ca, and Mg salts. Humic acid
effectively stabilized the MWNTs by steric interactions. The second part
will demonstrate the use of surface-modified nano-scale zero-valent iron
(NZVI) for remediation of dense non-aqueous-phase liquid (DNAPL).
Surface modification using novel block-copolymer and surfactants
enhanced transport through porous media. Amphiphilic block copolymer
modification helped the NZVI to localize at DNAPL/water interface. The
concluding part of the talk will focus on my research interests that include
studying the effect of functionalization on CNT aggregation and deposition
Dept: Of Mechanical Eng 2 PKCET, Kandala
NANOMATERIALS Seminar: 2013
behavior, development of nano-sensors for microbial mapping of the
subsurface, and toxicity of CNTs to microbes.
CONTENTS
INTRODUCTION……………………………………………………………….5
DEFINITION ……...……………………………………………………………6
ADVANCES IN NANOMATERIALS…....……………………………………8
TYPES OF NANO MATERIALS……………………….……………………..9
NANOMATERIAL COMPOSITION………...……………………………….14
PROPERTIES OF NANOMATERIALS…………….………………………..15
APPLICATIONS OF NANO MATERIALS…………………………….…….18
SAFETY……………………………………………………………………….24
DISADVANTAGES………………………………………………………...…25
CONCLUSION………………………………………………………………...27
BIBILIOGRAPHY……………………………………………………………..29
Dept: Of Mechanical Eng 3 PKCET, Kandala
NANOMATERIALS Seminar: 2013
LIST OF FIGURES
“HOW BIG IS 1 NANOMETER”
FULLERENES
OPTICAL PROPERTIES
ELECTRICAL PROPERTIES
MICROBIAL FUEL CELL
CARBON NANOTUBE
NANOWIRES FOR JUNCTIONLESS TRANSISTORS
Dept: Of Mechanical Eng 4 PKCET, Kandala
NANOMATERIALS Seminar: 2013
INTRODUCTION
Nanomaterials are chemical substances or materials that are manufactured
and used at a very small scale (down to 10,000 times smaller than the
diameter of a human hair).
Nanomaterials are developed to exhibit novel characteristics (such as
increased strength, chemical reactivity or conductivity) compared to the
same material without nanoscale features.
Hundreds of products containing nanomaterials are already in use.
Examples are batteries, coatings, anti-bacterial clothing etc. Analysts
expect markets to grow to hundreds of billions of Euros by 2015.
Nano innovation will be seen in many sectors including public health,
employment and occupational safety and health, information society,
industry, innovation, environment, energy, transport, security and space.
Nanomaterials have the potential to improve the quality of life and to
contribute to industrial competitiveness in Europe. However, the new
materials may also pose risks to the environment and raise health and
safety concerns.
These risks, and to what extent they can be tackled by the existing risk
assessment measures in the EU, have been the subject of several opinions
of the Scientific Committee on Emerging and Newly Identified Health
Risks (SCENIHR). The overall conclusion so far is that, even though
Dept: Of Mechanical Eng 5 PKCET, Kandala
NANOMATERIALS Seminar: 2013
nanomaterials are not per se dangerous, there still is scientific uncertainty
about the safety of nanomaterials in many aspects and therefore the safety
assessment of the substances must be done on a case-by-case basis.
DEFINITION OF NANOMATERIAL
A natural, incidental or manufactured material containing particles, in an
unbound state or as an aggregate or as an agglomerate and where, for 50 %
or more of the particles in the number size distribution, one or more
external dimensions is in the size range 1 nm - 100 nm.
In specific cases and where warranted by concerns for the environment,
health, safety or competitiveness the number size distribution threshold of
50 % may be replaced by a threshold between 1 and 50 %.
By derogation from the above, fullerenes, graphene flakes and single wall
carbon nanotubes with one or more external dimensions below 1 nm
should be considered as nanomaterials.
The definition will be used primarily to identify materials for which
special provisions might apply (e.g. for risk assessment or ingredient
labelling). Those special provisions are not part of the definition but of
specific legislation in which the definition will be used.
Nanomaterials are not intrinsically hazardous per se but there may be a
need to take into account specific considerations in their risk assessment.
Therefore one purpose of the definition is to provide clear and
Dept: Of Mechanical Eng 6 PKCET, Kandala
NANOMATERIALS Seminar: 2013
unambiguous criteria to identify materials for which such considerations
apply.
It is only the results of the risk assessment that will determine whether the
nanomaterial is hazardous and whether or not further action is justified.
Today there are several pieces of EU legislation, and technical guidance
supporting implementation of legislation, with specific references to
nanomaterials. To ensure conformity across legislative areas, where often
the same materials are used in different contexts, the purpose of the
Recommendation is to enable a coherent cross-cutting reference.
Therefore another basic purpose is to ensure that a material which is a
nanomaterial in one sector will also be treated as such when it is used in
another sector.
Dept: Of Mechanical Eng 7 PKCET, Kandala
NANOMATERIALS Seminar: 2013
ADVANCES IN NANOMATERIALS
The history of nanomaterials began immediately after the big bang when Nanostructure were formed in the early meteorites. Nature later evolved many other Nanostructures like seashells, skeletons etc. Nanoscaled smoke particles were formed during the use of fire by early humans. The scientific story of nanomaterials however began much later. One of the first scientific report is the colloidal gold particles synthesised by Michael Faraday asearly as 1857. Nanostructured catalysts have also been investigated for over 70 years. By the early 1940’s, precipitated and fumed silica nanoparticles were being manufactured and sold in USA and Germany as substitutes for ultrafine carbon black for rubber reinforcements.Nanosized amorphous silica particles have found large-scale applications in many every-day consumer products, ranging from non-diary coffee creamer to automobile tires,optical fibers and catalyst supports. In the 1960s and 1970’s metallic nanopowders for magnetic recording tapes were developed. In 1976, for the first time, nanocrystals produced by the now popular inert- gas evaporation technique was published by
Dept: Of Mechanical Eng 8 PKCET, Kandala
NANOMATERIALS Seminar: 2013
Granqvist and Buhrman. Recently it has been found that the Maya blue paint is a nanostructured hybrid material. The origin of its color and its resistance to acids and biocorrosion are still not understood but studies of authentic samples from Jaina Island show that the material is made of needle-shaped palygorskite (clay) crystals that form asuperlattice with a period of 1.4 nm, with intercalates of amorphous silicate substrate containing inclusions of metal (Mg) nanoparticles. The beautiful tone of the blue color is obtained only when both these nanoparticles and the superlattice are present, as has been shown by the fabrication of synthetic samples.
TYPES OF NANOMATERIALS
For the purpose of this article, most current nanomaterials could be
organized into four types:
• Carbon Based Materials
• Metal Based Materials
• Dendrimers
• Composites
Carbon Based Materials
Dept: Of Mechanical Eng 9 PKCET, Kandala
NANOMATERIALS Seminar: 2013
These nanomaterials are composed mostly of carbon, most commonly
taking the form of a hollow spheres, ellipsoids, or tubes.
Spherical and ellipsoidal carbon nanomaterials are referred to as
fullerenes, while cylindrical ones are called nanotubes.
These particles have many potential applications, including improved
films and coatings, stronger and lighter materials, and applications in
electronics.
Metal Based Materials
These nanomaterials include quantum dots, nanogold, nanosilver and metal
oxides, such as titanium dioxide.
A quantum dot is a closely packed semiconductor crystal comprised of
hundreds or thousands of atoms, and whose size is on the order of a few
nanometers to a few hundred nanometers.
Changing the size of quantum dots changes their optical properties.
Dendrimers
These nanomaterials are nanosized polymers built from branched units.
The surface of a dendrimer has numerous chain ends, which can be tailored
to perform specific chemical functions.
This property could also be useful for catalysis. Also, because three-
dimensional dendrimers contain interior cavities into which other
molecules could be placed, they may be useful for drug delivery.
Dept: Of Mechanical Eng 10 PKCET, Kandala
NANOMATERIALS Seminar: 2013
Composites
Composites combine nanoparticles with other nanoparticles or with larger,
bulk-type materials.
Nanoparticles, such as nanosized clays, are already being added to products
ranging from auto parts to packaging materials, to enhance mechanical,
thermal, barrier, and flame-retardant properties.
Materials referred to as "nanomaterials" generally fall into two categories:
fullerenes, and inorganic nanoparticles.
Fullerenes
The fullerenes are a class of allotropes of carbon which conceptually
are graphene sheets rolled into tubes or spheres. These include the carbon
nanotubes(or silicon nanotubes) which are of interest both because of their
mechanical strength and also because of their electrical properties.