ZeroG and Sticky Nano Property

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ZeroG and StickyNano Property 12
All things stick to each other at the
nanoscale. Gravity can be completely ignored.
Forget Gravity.
Objects tend to stick
Objects dont fall. No gravity
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Why no Gravity??
All objects in the universe are subject to
gravitational force
The Gravitational force is proportional to mass.
The masses of atoms,molecules and other nano
objects are vanishingly small.
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Why no Gravity??
An individual water molecule weighs 18 amu or 18
g/mol. 18 g/mol / (61023 atoms/mol) 3 10
-23 g Or 7 10-26 pounds 0.0000000000000000000000
0007 lbs. This weight is billions of times lower
than the other forces acting on the water
molecule.
H20 Weight 310-22 N Van der Waals Forces
10-12 10-10 N Covalent Bonds 10-9 N
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Gr. weak, Stickiness Strong
Forces between atoms and molecules
dominate. Electrostatic and Steric in origin.
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Electrostatic Forces
_
Electric Charges Positive and Negative
_
Opposite Charges Attract Like Charges Repel.
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Atoms
Electrons electrical charge -e
Bohr Model
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How sticky is it?
Our intuition based on our macroscopic world
fails us here. In general objects dont stick in
our daily lives.
Its Very Sticky down there
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Stickiness Bonding
Many types of bonding Two main categories Chemica
l and Physical
Chemical Bonds are very strong (intra-molecular) P
hysical Bonds are much weaker (inter-molecular)
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Chemical Bonds
Atoms interact chemically to form molecules
Molecule A group of atoms connected by chemical
bonds
Atom 2
Atom 1
They share / trade electrons
Molecule
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Chemical Bonds
Water
Carbon nanotubes
Gold nanocluster
Protein
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Chemical Bonds
Different Types of Chemical Bonds

• Covalent Bonds
• Ionic Bonds
• Metallic Bonds

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Chemical Bonds 1 Covalent Bonds
Atoms SHARE electrons
strc.herts.ac.uk/bio/markr/ biology/day1.htm
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Chemical Bonds 2Ionic Bonds
Atoms TRADE electrons
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Ionic Bonds
Atoms TRADE electrons
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Chemical Bonds 3 Metallic Bonds
Atoms DONATE MOBILE electrons
electron
Atom
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Physical or Intermolecular Bonds
Interactions between molecules
Molecules interact but remain independent. No
sharing of electrons.
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Physical Bonds
Different Types of Physical Bonds

• Van der Waals
• Hydrogen Bonds
• Hydrophobic Interactions

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Physical Bonds are Electrostatic in origin
Nano Object Neutral Charge equal positive and
negative charge
An object of neutral charge can be polarized.
-

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Van der Waals forces Polarizability 1
Polarized Object
Polarized Object
Dipole- Dipole interaction. Attractive. Sticky
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Van der Waals forces Polarizability 2
Polarizable Object
Dipole-Induced Dipole Interaction Attractive.
Sticky.
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Van der Waals forces Polarizability 3
Polarizable Object
Polarizable Object
Induced Dipole- Induced Dipole Interaction.
Attractive. Sticky.
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Van der Waals Bonding
Different Types of Physical Bonds

• dipole - dipole
• dipole - induced dipole
• induced dipole induced dipole

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Hydrogen Bonding
Hydrogens have a slight positive charge
Water
Oxygen has a slight negative charge
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Hydrogen Bonding
Hydrogen Bond
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(No Transcript)
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Hydrogen Bonding DNA
Base Pairing
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Hydrophobic Bonding
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Micelles/Detergents/Fatty Acids
Hydrophillic
water
Hydrophobic
water
water
water
water
water
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Micelles/Detergents/Fatty Acids
water
water
water
water
water
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Micelles/Detergents/Fatty Acids
water
water
water
water
water
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Micelles/Detergents/Fatty Acids
Hydrophillic
water
Hydrophobic
water
water
oil
water
water
water
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Micelles/Detergents/Fatty Acids
water
water
water
oil
water
water