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PhD Course
TOPICS IN (NANO)
BIOTECHNOLOGY
Nanoscale Imaging
and Nanoparticles
June 9th, 2004
Nanoscale Imaging

• SEM
• TEM
• Scanning Probe Microscopy
• Scanning tunnelling microscopy
• Atomic force microscopy
• Others
Field Ion Microscope
• First instrument providing images of atoms.

• Principle of operation is field ionisation (closely
related to field emission).

• An imaging gas is introduced, these gas atoms
approach the emitter, hop about until they are
accommodated to the emitter temperature and are
then ionised in the high-field regions above
protruding atoms.

• These ionised atoms then fly along the field
lines and produce spots on the fluorescent screen
corresponding to the protruding emitter atom.
Field Ion Microscope

FEM & FIM are only useful for samples which can be formed into
very sharp tips.
Electron Source (Themionic GUN)
Transmission Electron Microscope
• Specimens for examination under the transmission
electron microscope (TEM) must be specially
prepared to a thickness that permits the passage of
electrons (50-500 nm). As the wavelength of
electrons is much smaller than that of light, the
resolution attainable in TEM images is many orders
of magnitude better than that of a light microscope.
Transmission electron microscopes can reveal the
finest internal details of a cell.

• For biological samples, cell structure and morphology
is commonly determined whilst the localisation of
antigens or other specific components within cells is
readily undertaken using specialised preparative
techniques.

• Atomic resolution possible
Transmission Electron Microscope
Transmission Electron Microscopy
Paramyxovirus Flu Virus

Herpes Virus
Collagen Fibres
Scanning Electron Microscope
• By scanning an electron beam across a
specimen and collecting electrons emitted
from the irradiated spot we can obtain
topographical and chemical information on
materials from the macroscopic scale to very
high magnifications with great depth of field in
focus.
• Resolution ~1 nm.
Scanning Electron Microscope
SEM vs TEM
Scanning Electron Microscopy
Hibiscus Pollen

Beetles Skin

Holm Oak Leaf

Penicillin Spores

Mosquito Antennae
Scanning Probe Microscopy
• Scanning Tunnelling Microscopy
• Atomic Force Microscopy
• Others
Scanning Probe Microscopes
• SPMs are a family
of instruments
used for studying
properties of
materials from the
atomic to the
micron level.
Scanning Tunnelling Microscopy
• Invented 1981 (Binnig & Rohrer)
• Use sharpened, conducting tip with a bias voltage
applied between the tip and the sample.
• Within ~1 nm of the sample, electrons tunnel
between the tip and the sample (direction depending
on the sign of the bias voltage).

• This tunnelling current varies exponentially with the
tip-to-sample spacing.

• Tip and sample must be conductors or
semiconductors (cannot image insulating materials).

• Measures a surface of constant tunnelling probability
(not the physical topography!)
Scanning Tunnelling Microscopy
Scanning Tunnelling Microscopy

Sub-angstrom
vertical &
atomic lateral
resolution.
Scanning Tunnelling Microscopy
Imaging Modes

• Constant Height
– Fast
– Only useful for smooth
surfaces

• Constant Current
– Slower
– Good for irregular
surfaces
STM Images
Atomic Force Microscopy
• An AFM probes the surface of a sample with a sharp tip.
Tip located at the free end of cantilever that is 100-200
m long.

• Forces between the tip and cantilever cause the
cantilever to bend and/or twist.

• This deflection is measured as the tip is scanned over
the surface, providing a map of the surface topography.

• AFMs can be used to study insulators and conductors.

• AFMs can be operated in air, vacuum, and in liquids.
Biological measurements, in particular, are often carried
out in vitro in biological fluids.
Atomic Force Microscopy
Common detection schemes

• Optical lever
• Optical interference
• Piezoelectric effect
•…

0.1 mm
Atomic Force Microscopy
Interaction Forces
• Van der Waals
• Contact mode
– Close
– Repulsive
• Non-contact mode
– 1’s – 10’s of nm tip
- sample
separation
– Attractive

F = 0 @ ~0.2nm (length of chemical bond)
Contact (Repulsive) Mode AFM
• AFM tip makes soft physical contact with
the sample.

• Contact force causes the cantilever to
bend to accommodate changes in
topography.

• Cantilever spring constant less than
effective spring constant holding atoms
together in sample.

• F ~ 10-7 – 10-6 N
Non-Contact (Attractive) Mode
• Vibrating stiff cantilever (100 – 400 Hz)
• Amplitude 1’s – 10’s nm
• Spacing 1’s – 10’s nm
• Total force ~10-12 N
• Detect changes in frequency or amplitude of the
cantilever caused by changes in the force
gradient (slope of force-distance curve).
• Height resolution better than 0.1nm
• Good for soft and/or elastic samples
• No contamination of sample by tip
Contact vs Non-Contact Mode
Comparison
• Non-Contact
– Low damage
– Less sensitive to fine
topographical detail

• Contact
– Can damage soft samples
through lateral forces
(dragging material)
Contact Mode AFM Images

300 nm

150150 m2
Tapping Mode AFM
• Similar to non-contact
mode, but at bottom of
travel the tip just ‘taps’ the
sample surface

• Oscillation amplitude is
monitored

• Eliminates lateral forces
(friction /drag)

• Excellent for soft samples
(e.g. biological samples, LB
films, etc.)

• Tapping Mode overcomes
problems associated with
friction, adhesion, and
electrostatic forces
AFM in the Life Sciences
• Fundamental Challenges of Microscopy in
Biology:
– to preserve the specimen accurately in the native state
– to achieve sufficient resolution to learn something
useful about the structure/function of the specimen

• AFM is a breakthrough technology that allows
three-dimensional imaging and measurement of
unstained and uncoated structures in air or fluid
from molecular to micron scales
– scanners can now be immersed in liquids without
damage, allowing direct examination of samples in
biological fluids, water, or fixation media such as
glutaraldehyde or ethanol
AFM in the Life Sciences
• In addition to topographic imaging, the AFM can be
used simultaneously to measure forces on active
biological specimens, offering insight into cellular
and even molecular dynamics.

– Countless biological processes - muscle contraction, cell
motility, DNA replication, protein synthesis, drug-receptor
interactions, and many others - are largely governed by
intermolecular forces. And with its sensitivity at the
piconewton-level, the AFM is an excellent tool for probing
such interactions.

• There is increasing use of AFM probes that have
been chemically tailored to sense a specific
biological reaction or interaction (e.g. binding forces
between individual ligand-receptor pairs, cell
adhesion, antibody or DNA-based assays).
Tapping Mode AFM in Biology
E-coli

erythrocyles
Tapping Mode AFM in Biology

Successive tapping mode images under liquid of living
endothelial cells (scan size 70 microns)

Collagen fibres Human Bone Dynamics of Protein Adsorption
(collagen fibers & hydroxyapatite crystals) (lysozyme on a new contact lens over time)
Lateral Force Microscopy
• LFM measures the lateral deflections
(twisting) of the cantilever parallel to the
plane of the sample surface
• Useful for imaging e.g. composition
variations not associated with topography,
and for separating topographic and
composition variations.
• Also sensitive to changes in the surface
slope.
• Usually collect both AFM and LFM images
simultaneously.
Lateral Force Microscopy
LFM Images
scan direction scan direction

1 m 1m

step

22 m2 0.40.4 m2 0.40.4 m2
NANOPARTICLES AND
NANOPARTICLE APPLICATIONS
Overview
• Definition and Significance
• Synthesis and Characterization
• Stabilization
• Ordering
• Optical Properties
• Magnetic Properties
• Catalysis
Definitions
Nanoparticle - Particle with 1 dimension in the 10-100 nm size
range.
Colloid - Particle with dimensions in the 1 nm – 1 mm size
range.
Quantum Dot - Particle with all 3 dimensions in the 1-10 nm
size range.
Latex - Aqueous suspension of polymer particles.
Natural - Contains Protein Impurities; May Cause Allergies
Synthetic - Made via Emulsion Polymerization

Significance
The size of Nanoparticles leads to unique characteristics.
Metallic Nanoparticle Synthesis
M+ + Reductant Nanoparticle

M+ M+
M+ + + + ne-
M M M

M+

M = Au, Pt, Ag, Pd, Co, Fe, etc.
Reductant = Citrate, Borohydride,
Alcohols

Shipway, A.N.; Katz, E.; Willner, I. CHEMPHYSCHM.
Control Factors
Average Size
Reductant Concentration
Stirring Rate
Temperature
Size Distribution
Rate of Reductant Addition
Stirring Rate
Fresh Filtered Solutions
Stabilization
Solution Composition
Functionalized Reductions
M+ Functionalized
+ Reductant
Surfactant Nanoparticle
X
X

X
X

Y Y
Y
Y X
X Y
Y
Y
Y
Y
Y

X
X

Shipway, A.N.; Katz, E.; Willner, I. CHEMPHYSCHM. 2000, 1, 18-52.
Bimetallic Nanoparticle
Core-Shell

M1+ + M1
Reductant

M1 + M2+ + M1 M2
Reductant

Mixed Alloy

M1 + + M 2 + +
Reductant

Toshima, N.; Yonezawa, T. New Journal of Chemistry 1998,
1179-1201.
Semiconductor nanoparticles
(Q-dots)
R Se Se R
N C C
R C Se d Se N R
200º TOP/TOP
C O

O
P
CdSe O
P
P
OP
O

Nigel L. Pickett et al. The Chemical Record 2001, 1, 467-479
Micellar Encapsulation
Organic Nanoparticles

Dieter Horn et al.
Angew. Chem. Int.
Ed
Organic compound Water +
2001, 40, 4330-
+ Lipophilic solvent Stabilizer
4361

Emulsification Hydrosol of organic
compound

Separation
of solvent
Organic Nanoparticles
Polymer Nanoparticle Synthesis
X X
X X X
X
Micelle
X
X formed from
X emulsifier
X

X
X

X X

X Monomer X

X X
Polymer
X
X

X Stability Sphere
X X
X X

X X
X
X X X

Initiator
Electrostatic spray assisted vapour
deposition
Plasma Vaporisation
Other Techniques
Laser Ablationa
Electrochemistryb
Hydrothermal Synthesisc
(Supercritical water)
Sol-Geld

a: Neddersen, J; et. al. Appl. Spec. 47 p. 1959-1964 (1993)
b: Lu, D; Tanaka, K. J. Phys. Chem. 100 p. 1833-1837 (1996)
c: Cabanas, A; Poliakoff, M. J. Mater. Chem. 11 p. 1408-1416 (2001)
d: Moreno, E; et. al. Langmuir 18 p. 4972-4978 (2002)
Characterization
Technique Information

TEM/SEM Size/Shape/Size Distribution

UV/vis Size/Size Distribution

AFM Size/Shape/Size Distribution

X-ray Composition

Zetasizer Size/Size Distribution
Stabilization of Polymer Nanoparticles
•Stable Dispersion- All particles exist as single entities; order or
disorder
•Aggregation- General term for unstable states
•Flocculation- Disorder, with weak attraction
•Coagulation- Disorder, with strong attraction Coagulated

Low [electrolyte]
Aggregated
Strong repulsion
Order
Intermediate Flocculated
[electrolyte]
Stable
Repulsive contacts High
Disorder [electrolyte]
Forces to Consider
1. Electrostatic- Charged surfaces and stabilizers
2. Steric- Geometric effects/Solvation effects
3. van der Waals- Attraction of polymer chains
towards each other
X X X
X X X

X
X

X
X X
X, Y = Cationic,
X
X
Anionic, or Nonionic
X

Y
Y Y
Y
X
Functional Groups
Y
X X
Y
Y
Y
X Y Y X

X
X

X X
X X

X X
X
X X X
Ionic Groups -
- - - -- Stabilizer
-
- - -- - - - --
-- - - - --
- OR -
- - -- - - --
-- --
Neutralization of
surface charge causes
Tails bind via
aggregation More hydrophobic
Stabilizer attraction- enhanced
stability

- - - --
-
- - -- Hydrophobic attraction
-- binds tails, leading to an
excess of positive charge-
stabilization
Nonionic Groups

Hydrophobic interactions bind
- - - --
-
- - -- the tail group to the NP, while
--
the polar head groups extend into
solution

The polar head groups are hydrated,
providing a steric barrier to prevent
aggregation
Surface Charges

r = Potential at distance r from NP -+ + +
surface - -+ - +
+ + - -- +
-
s = Potential at NP surface + - - - - -- +
+ + + +
a = radius of NP -
+ +
r = distance from NP surface
a  r a 
r  s e
e = elementary charge
NA = Avogadro’s number r
 = Permittivity of free space
k = Boltzmann’s constant
Where:
T = Temperature
8e N A 2
 
I = Ionic Strength 2
I
1000 kT
Effect of Electrolyte Concentration on Potential Profiles

0.9

0.8

0.7

0.6

 0.5

0.4

0.3

0.2

0.1

0
0 1 2 3 4 5 6 7 8 9 10
Distance

C1
C1 > C2
C2
Interaction Energy
Vt = Vr + Va Where
Vr = Potential energy of electrostatic
interactions (may include contribution from
steric interactions
Va = Potential energy of van der Waals
interactions
Vr Double layer term (DLVO theory) surface
charge & environment (electrolyte & solvent);
thickness and density of adsorbed layer and
interaction with solvent
Va Material nature (dispersion frequency, static
polarizability, density)- Hamaker constants*
*An estimate of the Hamaker constant may be determined from AFM
measurements: Argento, C.; French, R. H. Journal of Applied Physics
1996, 80, 6081-6090.
DLVO Theory

Repulsion

Vr + Va
0

Attraction

0 Separation Distance (nm) 200
Nanoparticle Films
Ligand Directed Assembly

nanoparticle
substrate +
Bifunctional
ligand

+
Ligand Directed Assembly
• Monolayer formed by
adsorption of Au particles on 3-
mercaptopropyltrimethoxysilane
derivatized SiO2 surface

• Multilayers constructed by
immersion in a 5mM solution of
2-mercaptoethanol for 10 min.
followed by immersion in Au
particle solution for 40 – 60
min.
Tapping mode AFM (1mm x 1mm) of HSCH2CH2OH linked Au colloid
multilayers: (A) monolayer; (B) 3 Au treatments; (C) 5 Au treatments;
(D) 7 Au treatments; (E) 11 Au treatments.
Natan, M. J.; et. al. Chem. Mater. 2000, 12, 2869-2881
Electrostatic Assembly
-- - + - --
+ +
+ -
-- -- --
- --
• Polycationic polymer
• Very stable in most solvents
• Control inter-layer spacing
• Conductive, semiconductive, or insulating

Shipway, A.N.; Katz, E.; Willner, I. CHEMPHYSCHM. 2000, 1, 18-52.
Convective Self Assembly
• Definition: Particles are allowed to freely
diffuse. As the solvent evaporates, particles
crystallize in a hexagonally close-packed array.
• Optimize: Particle concentration
Particle/Substrate charge
Evaporation

Top
View

Colvin, V.L.; et. al. J. Am. Chem. Soc. 1999, 121, 11630-11637.
Photolithography Patterning
• Typically pattern the capture monolayer
followed by particle adsorption

• Few examples of patterning after
nanoparticle deposition
Photolithography Patterned Nanoparticles

SEM image of Au
nanoparticles adsorbed
onto a patterned (3- AFM image (80 mm x 80
mercaptopropyl)- mm) of a three-layer
trimethoxysilane coating of nanoparticles
monolayer on SiO2 followed by
coated Silicon wafer. photopatterning.
Electron Beam Lithography
• Typically:
– coat substrate with polymer film
– write pattern with e- beam
– dissolve exposed polymer
– evaporate metal into “holes”

Somorjai, G. A.; et. al. J. Chem. Phys. 2000, 113(13), 5432-5438.
Images of Nanoparticle Arrays formed
by Electron Beam Lithography
Spin-coat PMMA on Si(100)
wafer with 5nm thick SiO2 on
surface.
Beam current: 600pA
Accelerating Voltage: 100dV
Beam diameter: 8nm
Exposure time: 0.6s at each
site
Pt deposition: 15 nm by e-
beam evaporation
AFM and SEM of Pt nanoparticle array. Particles are
40nm in diameter and spaced 150nm apart.
Nanosphere Lithography

(A) Representation of a single-layer
nanopshere mask formed by
convective self assembly.
(B) Illustration of the exposed sites on
the substrate with single-layer mask
(C) AFM image (1.7mm x 1.7mm) of Ag
deposited on mica with a mask of
264nm diameter nanoparticles.
Mask preparation: Spin coat 267 nm polystyrene
nanoparticles at 3600 rpm.
Deposition: Ag vapor deposition
Mask removal: sonicate 1-4 min. in CH2Cl2

Hulteen, J.C.; Van Duyne, R.P. J. Vac. Sci. Technol. A 1995,
13(3), 1553-1558.
Microcontact Printing
• PDMS stamp to “ink” a capture monolayer on a
substrate followed by nanoparticle adsorption
• PDMS stamp to “ink” the nanoparticles directly
onto the substrate

Side
View
Top
View

Shipway, A.N.; Katz, E.; Willner, I. CHEMPHYSCHM.
2000, 1, 18-52.
AFM of Microcontact Patterned
Nanoparticle Array

AFM scan (10m x 10m) of
microcontact printed Au
surfaces. HOOC(CH2)15SH is
initially stamped on substrate.
The surface is then exposed to
1.0 mM 2-mercaptoethylamie
followed by exposure to a
17nM solution of 12nm Au
nanoparticles.

Natan, M. J.; et. al. Chem. Mater. 2000, 12,
2869-2881
Optical Properties and
Applications of Nanoparticles
Plasmon Absorbance
Surface-Enhanced Raman Spectroscopy (SERS)
Fluorescence Spectroscopy
Plasmon Absorbance

• Surface Plasmon (SP): Coherent oscillation in e-
density at the metal and dielectric interface when e-
field (of incident light) forces loosely held conduction
electrons to move with the field
• Plasmon absorbance : absorption of e-magnetic
radiation of SP at a particular energy
Plasmon Absorbance - Factors
• Surface functionality, temperature, and the
solvent
• Particle concentration and particle size
Plasmon absorbance - Applications
• Coupled – Plasmon 1
Absorbances

2
Plasmon absorbance – Applications

James J. Storhoff et al. J. Am. Chem. Soc., 120 (9), 1959 -1964,
SERS - Background
• Enhanced e-magnetic field as a consequence of SP
and the appearance of new electronic states in the
absorbate as a consequence of absorption

• Enhancement occurs when the exciting radiation is
coincident with the plasmon absorbance of the
nanoparticles

• Aggregated nanoparticles have additional plasmon
resonances associated with interparticle plasmon
coupling
SERS - Factors
• Particles size

Shuming Nie et al. J. Am. Chem. Soc. 1998, 120,
SERS - Applications
Laser
Raman
signal to
detector

Au nanoparticle
with Raman
label and
antibody

Antibody Linker molecule
Antigen Raman Reporter
(analyte) molecule
Application - Analysis of Prostate Specific
Antigen (PSA)
Raman spectra of PSA assay

35000

30000
1000 ng/mL
25000
100 ng/mL
intensity

20000
10 ng/mL
15000
0 ng/mL
10000

5000

0
200 400 600 800 1000 1200 1400 1600 1800 2000
Raman shift (cm-1)

PSA: Prostate cancer marker. Different forms. Analysis of
composition change gives information of the malignancy
Fluorescence - Applications

Bioconjugated
fluorescent
nanoparticles –
Probing specific DNA
sequences

Shuming Nie et al. Anal. Chem., 72 (9), 1979 -1986, 2000.
Fluorescence – Applications

Shuming Nie et al. Anal. Chem., 72 (9), 1979 -1986, 2000.
Magnetic Nanoparticles
• Small size implies superparamagnetism
• Ferrofluids: a colloidal mixture of
magnetic nanoparticles
• Generally made through a reduction
reaction, however, other methods have
been used
– Hydrothermal Synthesis
– Laser Ablation
Magnetic Cell Sorting
Modify MP by attaching an effector

MP MP

Roger, Pons, Massart, et. al. Eur. Phys. J. AP 5,
321-325 (1999)
Bind to Specific Cells

MP MP
Cell Cell

MP MP

MP + MP

MP
Cell MP

Cell
MP
MP
Uses for magnetically labeled cells

A: Cell sorting B: Magnetic Fluid
Hyperthermia

Jordan, A. et. al. J Magn Magn Mater, 201 (1999) 4

Roger, J.; et. al. Eur. Phys. J. AP 5, 321-325
(1999)
Magnetic Fluid Hyperthermia (MFH)
• Also known as magnetocytolysis
• Inject fluid containing MP’s into patient
• Use constant magnetic field to
maneuver particles to desired location
(tumor, for example)
• Expose area to oscillating magnetic field
to cause extremely localized heating
• Prototype unit being built in Germany

Jordan, A. et. al. J Magn Magn Mater, 201 (1999) 413-419
Magnetic Recording Media
Can be manufactured through a 6 step process

Left: synthesis
scheme.

Right: SEM image of
substrate. a)before
step (f). b)same array
filled with nickel c)
MFM (12mm x 12 mm)
image of array.
Magnetic Recording Media
Each nickel “column” has dimensions on the
order of 170 nm diameter, 200 nm high and
2 m apart. This leads to a particle density
below that of today’s hard drives (by
approximately a factor of 10), however, it
demonstrates that other methods for data
storage are feasible. This method can be
used with current read/write heads
Nanomotors/generators using
Ferrofluids

Zahn, M. J. Nano. Rsrch, 3: 73-78, 2001
Nanomotors/generators using
Ferrofluids
• Currently, it appears that very few
applications explored (mostly theoretical)
• Paradoxical results
– below a critical magnetic field strength,
ferrofluids move opposite an AC field.
– Fluid viscosity is dependent on the field
strength (zero viscosity fluid reported)

Ref’s in review: Zahn, M. J. Nano. Rsrch. 3: 73-78, 2001
Drug Targeting/Gene
Transfection Studies
Both are methods of delivery using magnetic
fields.
Magnetic Particles with the appropriate ligands
attached are injected into the body and
manipulated to the positions where they will be
activated using magnetic fields.
At this point, the gene/drug will be taken up by
the cell and act as it is supposed to (depending
on the application)
Often used in conjunction with MFH
Scherer, F; et. Al. Gene Therapy, 9 p. 102-109 (2002)
Other Possible Uses for Magnetic
Nanoparticles

• MRI Contrast Enhancementa
• GMR detection methods b

• Magnetocaloric refrigerationc

a: Ahrens, E. T; et al. Proc. Natl. Acad. Sci. USA: 95 p. 8443-8448
(1998)
b: Tondra, M; Porter, M; Lipert R; J. Vac. Sci. Tech. A: 18 p. 1125-1129
(2000)
c: McMichael, R. D.; et al. J. Magn. Magn. Mater. 111 p. 29-33 (1992)
Catalysis
Au nanoparticles supported on TiO2 substrates show high
activity for oxidation of CO at room temperature and
below.
Reaction proceeds at corner,
step, and edge sites of Au
CO adsorption
3.5 nm Au nanoparticle
(on Au)
12 Atoms in length
Oxygen
Adsorption 2-3 Atoms
(on TiO2) high

TiO2 Support

Haruta, M.; Date, M. Applied Catalysis A: General 2001, 222, 427-437.
Bimetallic Catalysis
CH2=CH-CN + CH2=CH-
H2O CONH2

CH3-CH-
CN O
H
Reaction proceeds most
favorably with Pd-Cu particles,
and is 100% selective when
Geometric effects lead to using a 3:1 Cu:Pd ratio.
higher activity and
selectivity for certain
reactions.
Effect of Composition
Interaction of the two metals:
e-
density
Pd Pt

Catalytic activity as a
function of nanoparticle
composition for the
hydrogenation of 1,3- C=C bond prefers e- deficient
Cyclooctadiene sites (donor acceptor
interactions); leads to
selective hydrogenation
Electrochemical Reactions
• Electrochemistry using a roughened silver
electrode has been compared to that using an array
of silver nanoparticles on a support.
• Different molecules adsorb differently on the two
surfaces; i.e. there are different types of active sites.

CVs of methylviologen in 0.1 M
Na2SO4 at
(a) EC roughened electrode,
and
(b) NP array electrode
Surface Comparison
Ag Electrode polished,
SEM then roughened by
potential steps in 0.1 M
images of KCl
(A) EC NP array made by dipping
roughened an Indium-Tin Oxide
electrode (ITO) electrode in poly-L-
lysine for two hours, then
and (B) NP into a colloidal silver
array solution overnight
electrode
Defect sites on the EC roughened electrode
must be active for MV adsorption.
Zheng, J.; Li, X.; Gu, R.; Lu, T. Journal of Physical Chemistry B 2002, 106, 1019-1023.
Applications of Latex Particles
•Butadiene
•Tires, Belts, Cables, Shoes, etc.
•Oil-resistant Products
•Styrene
•Linoleum, Plastics, Coatings
•Vinyl Acetate
•Adhesives and Paints
•Acrylate
•Adhesives, Paints, Primers, and Leather Finishing
•Chloroprene
•Belts, Hoses, Cables, etc.
•Natural Rubber Latex
•Gloves
•Condoms
Drying of Paint
Homework
Select one article from the handout and make a
summary to explain the paper to your compañeros
in the next class.