OPA
④* *REEDID OFFFEINCONNOENGERSLIE
inanamescaterials:
what's
chemical substances or a re manufactured and used
materials that atthe nanoscale
created to exhibit novel characteristics (increased strength, chemical reactivity,
conductivity)
may pose risks to environment and raise health/safety concerns
many products already in use (batteries, coatings, anti-bacterial, etc.)
nano innovation effects many sectors:public health, employment, environment, etc.
Michael Faraday:
first
synthesis gold nanoparticles
of
discovered purple-red' gold
Richard Feynman
philosophical father nanotechnology
of
Feynman set challenges with $1000 prize
1. constructing a
tiny motor
2. fit encyclopedia britannia on the head of a pin
on the surface of things:
interface:surface that separates much larger volumes of
dissimilar substances
the assumption that there's no interface doesn't hold
for nanoparticles given the surface to volumeratio
(as shown on the right)
surface atoms possess dangling bonds
at corners / kinks/edges density of dangling
bonds increases
dangling bonds:bonds at surface when atoms have unfilled outer orbital (valence) shell
surface energy surface density dangling
of bonds x
energy of the bond
quantifies the disruption of intermolecular bonds that occur when a surface is created
depends on shape, roughness and chemical composition
higher surface energy makes a material less stable
surface pressure:pressure generated by surface energy
increases with increasing surface curvature
Laplace law:mathematical relation between spherical surface pressure, radius & surface energy
Ap 2(U(r)
=
to reduce surface energy, dangling bonds will react
size is everything.... Almost
nanochemistry falls between the classic and
quantum field (Inm-100nm)
different particles have different
optical
properties
Length of
synthesis reaction deter-
mine the particle size
④* *REEDID OFFFEINCONNOENGERSLIE
inanamescaterials:
what's
chemical substances or a re manufactured and used
materials that atthe nanoscale
created to exhibit novel characteristics (increased strength, chemical reactivity,
conductivity)
may pose risks to environment and raise health/safety concerns
many products already in use (batteries, coatings, anti-bacterial, etc.)
nano innovation effects many sectors:public health, employment, environment, etc.
Michael Faraday:
first
synthesis gold nanoparticles
of
discovered purple-red' gold
Richard Feynman
philosophical father nanotechnology
of
Feynman set challenges with $1000 prize
1. constructing a
tiny motor
2. fit encyclopedia britannia on the head of a pin
on the surface of things:
interface:surface that separates much larger volumes of
dissimilar substances
the assumption that there's no interface doesn't hold
for nanoparticles given the surface to volumeratio
(as shown on the right)
surface atoms possess dangling bonds
at corners / kinks/edges density of dangling
bonds increases
dangling bonds:bonds at surface when atoms have unfilled outer orbital (valence) shell
surface energy surface density dangling
of bonds x
energy of the bond
quantifies the disruption of intermolecular bonds that occur when a surface is created
depends on shape, roughness and chemical composition
higher surface energy makes a material less stable
surface pressure:pressure generated by surface energy
increases with increasing surface curvature
Laplace law:mathematical relation between spherical surface pressure, radius & surface energy
Ap 2(U(r)
=
to reduce surface energy, dangling bonds will react
size is everything.... Almost
nanochemistry falls between the classic and
quantum field (Inm-100nm)
different particles have different
optical
properties
Length of
synthesis reaction deter-
mine the particle size
