Introduction to Chemistry

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Introduction to Chemistry Background for
Nanoscience and NanotechnologyUEET 101

• Prof. Petr Vanýsek
• NIU Department of Chemistry and Biochemistry
• August 31, and September 2, 2010

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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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How to understand structures Space filling Wire
frame Ball and stick
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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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Nanotubes
Carbon nanotube extremely strong Theoretical
tensile strength 300 Gpa Highest reported 63
Gpa Kevlar 2.7 GPa steel piano wire 2.4
GPa spider silk 1 GPa diamond - up to 60 GPa
Single walled nanotube
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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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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 1. Discuss
each point and decide whether it is a useful or a
good value and design a test how to verify the
claim. 2. 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
1 H 2 He
3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne
11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar
19 K 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr
37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe
55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn
87 Fr 88 Ra 89 Ac 104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 112 113 114 115 116 117 118

58 Ce 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu
90 Th 91 Pa 92 U 93 Np 94 Pu 95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No 103 Lr
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Acceptance of nanotechnology