1. Nanotechnology involves manipulating matter at the nanoscale, between 1 to 100 nanometers. 2. One key difference between bulk and nanoscale materials is their surface area to volume ratio. Nanoparticles have a much higher surface area relative to their volume. 3. This large surface area to volume ratio allows for new material properties and applications. For example, it allows nanoparticles to serve as very effective catalysts by increasing the amount of surface available for chemical reactions.

1. Lecture 2
Learning Outcomes:
1. Surface to volume ratio and its effect
2. Surface states and its advantages

2. What Is Nano ?
Nanotechnology: A more generalized description of nanotechnology was subsequently established by
the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter
with at least one dimension sized from 1 to 100 nanometers.
IUPAC Definition: a nanoparticle is a particle of any shape with dimensions in the range of 10−9 to
10−7 m.
7
Introduction to nanotechnology

3. Introduction to nanotechnology
3
History of Nanotechnology
As far back as the fourth century, nanoparticles
were used by artisans for generating a glittering
effect on the surface of pots. One the left is a
famous artifact called the Lycurgus Cup resides
in the British Museum in London. What makes
this cup unique is that its color changes from
green (when illuminated from the outside) to red (when illuminated from
within) due to nanoparticles of gold and silver in the glass. Modern
scientific evaluation of colloidal nanoparticles did not begin until
Michael Faraday's work of the 1850s. He provided the first description,
in scientific terms, of the optical properties of nanometer-scale metals in
his classic 1857 paper. In 1959, Richard Feynman first introduced the
concept of nanotechnology in his talk “There's Plenty of Room at the
Bottom,” in which he described the possibility of synthesis via direct
manipulation of atoms. The term "nano-technology" was then first used
by Norio Taniguchi in 1974. With the invention of electron microscopes,
analyses on small matters become much easier. Thus research on
nanotechnology flourishes quickly. To date, nanotechnology has become
an interdisciplinary bridge due to unique properties of nanomaterials,
widely applied to pharmacy, therapeutics, electromagnetics and catalysis.

4. 4
Three (of several) Senses of Small
• Size and surface area effects
1 nm – 100 nm Fundamental materials
properties remain the same but size,
shape and surface area alter some
behaviors work function, solubility,
chemical potential, contaminate sorption
• Critical Size and Characteristic
Length Scale Interesting or unusual
properties because the size of the
system approaches some critical
length (includes quantum effects). Many
characteristics of material may have
normal or nearly normal behavior
• New (Non-extensive) Properties
Systems not large enough to have
extensive properties. Particles become
effectively polymorphs of “bulk” materials
and statistical homogeneity may not be
valid.
n = 1
n = 3
n = 2
n = 4
n = 5
Energy
/
(h
2
/8ml
2
)
25
16
1
4
9
0
size   d
V= correlation length
d = range of
intermolecular forces
• Kelvin equation for solubility
• Gibbs-Thompson relation for
chemical potential
What do we we mean by small particle and why does their chemistry change?

5. LENGTH SCALES

6. DIFFERENCE BETWEEN BULK AND NANOMATERIALS
BULK carbon as graphite
Nano carbon as graphene

8. AN EXAMPLE TO START WITH

9. THE FIRST DIFFERENCE
– SURFACE TO VOLUME

10. WHAT IT DOES ?
• The large surface area to volume ratio of nanoparticles opens many
possibilities for creating new materials and facilitating chemical processes.
In conventional materials, most of the atoms are not at a surface; they form
the bulk of the material.
• In nanomaterials, this bulk does not exist. Indeed, nanotechnology is
often concerned with single layers of atoms on surfaces. Materials with
this property are unique. For example, they can serve as very potent
catalysts or be applied in thin films to serve as thermal barriers or to
improve wear resistance of materials.

13. An example of nano and bulk coating on surface