Introduction to Chemistry – Background for Nanoscience and Nanotechnology

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Introduction to Chemistry Background for
Nanoscience and Nanotechnology

• Prof. Petr Vanýsek
• NIU Chemistry and Biochemistry

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Introduction to Chemistry Principles
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Introduction to measurements

• Distance/size
• dynamics of the scale from the wavelength of
  x-rays to astronomic distances.
• focus on the middle scale size from visible
  objects person, hand (where did inch come
  from?), fingernail thickness, hair diameter,
  mite, microbe, virus, finally atom and a
  molecule.

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Wide dynamic range of dimensions

• Electromagnetic spectrum

Relevant dimensions kilometers (103
m) meters centimeters (2-1/2 1
inch) millimeter nanometers Angstroms (10-10
m) size of an atom
Atom Electrons going around the nucleus
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The scale of things
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Units of Measurement

• SI Units
• There are two types of units
• fundamental (or base) units
• derived units.
• There are 7 base units in the SI system
• distance (length) is one of them
• the fundamental unit is meter

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Some measurements are too small or too large to
use the basic unit. Therefore, we use prefixes.
SI Units
Selected Prefixes used in SI System
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Why dimensions matter? Nanomaterials particles
of nanometer size
Nano-scale materials often have very different
properties from bulk materials e.g. color and
reactivity

• 3nm iron particle has 50 of atoms on the
  surface
• 10nm particle has 20 of atoms on the surface
• 30nm particle has 5 of atoms on the surface

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Temperature

• SI Units
• Other important unit is unit for temperature.
  Temperature relates to the state of matter (gas,
  liquid, solid) and is fundamentally important in
  materials science.

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Change of volume with temperature

• Thermal expansion volumetric thermal expansion.

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Mercury thermometer

• Gallium nanothermometer

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Forms of materialCARBON - GRAPHITE
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Forms of materialDIAMOND - GRAPHITE
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Form of materialGRAPHITE - FULLERENE
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Fullerenes
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Fullerenes
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Classification of Matter

• States of Matter
• Matter can be a gas, a liquid, or a solid.
• These are the three states of matter.
• Gases take the shape and volume of their
  container.
• Gases can be compressed to form liquids.
• Liquids take the shape of their container, but
  they do have their own volume.
• Solids are rigid and have a definite shape and
  volume.

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Properties of Matter

• Physical vs. Chemical Properties
• Physical properties can be measure without
  changing the basic identity of the substance
  (e.g., color, density, odor, melting point)
• Chemical properties describe how substances react
  or change to form different substances (e.g.,
  hydrogen burns in oxygen)
• Intensive physical properties do not depend on
  how much of the substance is present.
• Examples density, temperature, and melting
  point.
• Extensive physical properties depend on the
  amount of substance present.
• Examples mass, volume, pressure.

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Properties of Matter
Physical and Chemical Changes
2 H2 O2 ? 2 H2O
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Properties of Matter

• Physical and Chemical Changes
• When a substance undergoes a physical change, its
  physical appearance changes.
• Ice melts a solid is converted into a liquid.
• Physical changes do not result in a change of
  composition.
• When a substance changes its composition, it
  undergoes a chemical change
• When pure hydrogen and pure oxygen react
  completely, they form pure water. In the flask
  containing water, there is no oxygen or hydrogen
  left over.

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Why Study Chemistry?

• Chemistry is the study of the properties of
  materials and the changes that materials undergo.
• Chemistry is central to our understanding of
  other sciences.
• It is substantial part of nanoscience and
  nanotechnology

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The Study of Chemistry

• The Molecular Perspective of Chemistry
• Matter is the physical material of the universe.
• Matter is made up of relatively few elements.
• On the microscopic level, matter consists of
  atoms and molecules.
• Atoms combine to form molecules.
• As we see, molecules may consist of the same type
  of atoms or different types of atoms.

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Molecular Perspective of Chemistry
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Matter

• Solution A uniform mixture of two substances
  such that molecules are separate from each other
  and move around randomly. Usually these are
  liquids. Solutions are usually transparent.
• Colloids A mixture of much larger particles
  ranging from 20 nm to 100 µm. Milk and paint are
  colloids.
• Grains Some materials are made up of many small
  crystals called grains. A grain is an individual
  crystal of such a solid. Different grains may
  have the crystal lattice oriented in different
  directions.

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Grain Structure in Steel
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Elements, Atoms and Molecules

• Atoms All matter is made up of tiny particles
  called atoms.
• Molecules Sometimes two or more atoms are found
  bound together to form molecules.
• The atoms can be categorized into about 115
  different types based on the charge of the
  nucleus.
• Elements are made up of only one type of atom.
• The element carbon takes the form of graphite,
  diamond and buckminsterfullerene as well as
  others.
• It is only possible to change one type of atom
  into another through nuclear processes such as
  take place in a nuclear power plant, the sun,
  atomic bombs or particle accelerators.
• The elements do not change in ordinary chemical
  reactions.

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Diagram Atom of helium
Protons Electrons Neutrons Electrons, on the
outside, are responsible for bonds
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Chemical Bonding

• Covalent bonds
• Ionic bonds
• Metal bonding

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How to go about making materials?Through
chemistry
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Forms of materialCARBON GRAPHITE - DIAMOND
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Phase diagram for carbon
From F.P. Bundy, The P,T Phase and Reaction
diagram for elemental Carbon, 1979 J. Geophys.
Res. 85 (B12) (1980) 6930.
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How to go about making nanomaterials?
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Diamond is hard, has high thermal
conductivity It is desirable material, how to
make it synthetically
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Swiss Diamond Pan
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Now, please turn to your group mates and discuss
the questions. You have about 10 minutes to do
that. Write down your answers.
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Claims and/or facts Pressure Cast Aluminum for
non-warping and great thermal characteristics
with no hot spots. Reinforced Non-Stick
coating using Nano-Composite Technology with
Diamond Crystals. Perfectly flat bottoms for
cooking on all major surfaces. Ergonomic
Handles- oven safe 500ºF. Dishwasher and Metal
Utensil Safe. Patented Non-Stick Exclusive.
Hardest material known to man. Diamonds Make
the Difference! Perfect Heat Distribution The
8 pan cost (mail order) 55 As a chemist,
engineer, student, cook, consumer Discuss each
point and decide whether it is a useful or a good
value and design a test how to verify the claim.
Discuss what methods have to be mastered to make
such a pan. Where do you get the diamonds, for
example.
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Large diamonds, though not of the jewelry
quality, can be made at high pressures. How
about small particles with properties of diamond,
having also properties on nano-materials (e.g,
large surface to volume ratio. This has been
achieved by chemical vapor deposition (CVD).
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Why make nanodiamonds hard surface, good heat
conductivity, low adherence to water. Ideal
technological material for a household item A
frying pan.
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WHAT IS NANO?
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Top-down and bottom-up approach
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The top-down approach
Machining or etching larger blocks and composites
to smaller structures

• Compare to traditional sculpture
• Size of detailed features depends on size of
  tools

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The bottom-up approach
Small molecules or particles pre-designed to
self assemble into larger, organised structures
e.g. surfactants
Hydrophilic head group Water loving
oil
oil
oil
water
Hydrophobic tail Water hating
oil
oil
Spherical micelle
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The Periodic Table
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Acceptance of nanotechnology