A sputter coater may be purchased that deposits single layers of gold, gold-palladium, tungsten, chromium, platinum, titanium, or other metals in a very controlled thickness pattern. It is possible, and desirable, to coat only a few nm’s of metal onto the sample surface.
Spin coating
Many polymer films are depositing via a spin coater which spins a substrate (often ITO glass) and drops of polymer liquid are dispersed an even thickness on top of the substrate.
Staining
Another option for polymer sample preparation is staining the sample. Stains act in different ways, but typical stains for polymers are osmium tetroxide (OsO
4 ), ruthenium tetroxide (RuO
4 ) phosphotungstic acid (H
3 PW
12 O
40 ), hydrazine (N
2 H
4 ), and silver sulfide (Ag
2 S).
Examples
Comb-block copolymer (microstructure of cast film)
To view interior structure, the film was cut with a microtome or razor blade after the film was frozen in liquid N
2 and fractured.
Stained with RuO
4 vapor (after cutting).
Structure measurements were averaged over a minimum of 25 measurements.
SEM micrograph of comb block copolymer showing spherical morphology and long range order. Adapted from M. B. Runge and N. B. Bowden,
J. Am. Chem. Soc. , 2007,
129 , 10551. Copyright: American Chemical Society (2007).
Pressed polymer samples into disks and annealed for 16 h at 170 °C.
To determine ordered morphologies, the disk was fractured (see
[link] ).
Used SEM to verify lamellar spacing from USAXS.
SEM image of a fractured piece of polymer SL-1. Adapted from J. Rzayev,
Macromolecules , 2009,
42 , 2135. Copyright: American Chemical Society (2009).
Swnts in ultrahigh molecular weight polyethylene
Dispersed SWNTs in interactive polymer.
Samples were sputter-coated in gold to enhance contrast.
The films were solution-crystallized and the cross-section was imaged.
Environmental SEM (ESEM) was used to show morphologies of composite materials.
WD = 7 mm.
Study was conducted to image sample before and after drawing of film.
Images confirmed the uniform distribution of SWNT in PE (
[link] ).
M
W = 10,000 Dalton.
Study performed to compare transparency before and after UV irradiation.
SEM images of crystallized SWNT-UHMWPE films before (left) and after (right) drawing at 120 °C. Adapted from Q. Zhang, D. R. Lippits, and S. Rastogi,
Macromolecules , 2006,
39 , 658. Copyright: American Chemical Society (2006).
Nanostructures in conjugated polymers (nanoporous films)
Polymer and NP were processed into thin films and heated to crosslink.
SEM was used to characterize morphology and crystalline structure (
[link] ).
SEM was used to determine porosity and pore size.
Magnified orders of 200 nm - 1 μm.
WD = 8 mm.
M
W = 23,000 Daltons
Sample prep: spin coating a solution of poly-(thiophene ester) with copper NPs suspended on to ITO coated glass slides. Ziess, Supra 35
SEM images of thermocleaved film loaded with nanoparticles with scale bar 1 μm. Adapted from J. W. Andreasen, M. Jorgensen, and F. C. Krebs,
Macromolecules , 2007,
40 , 7758. Copyright: American Chemical Society (2007).
Used cryogenic SEM (cryo-SEM) to visualize the microstructure of particles (
[link] ).
Particles were immobilized by fast-freezing in liquid N
2 at –196 °C.
Sample is fractured (-196 °C) to expose cross section.
3 nm sputter coated with platinum.
Shapes of the nanoparticles after fracture were evaluated as a function of crosslink density.
Cryo-SEM images of plastically drawn polystyrene and latex particles. Adapted from H. Ge, C. L. Zhao, S. Porzio, L. Zhuo, H. T. Davis, and L. E. Scriven,
Macromolecules , 2006,
39 , 5531. Copyright: American Chemical Society (2006).
Bibliography
H. Ge, C. L. Zhao, S. Porzio, L. Zhuo, H. T. Davis, and L. E. Scriven,
Macromolecules , 2006,
39 , 5531.
J. Rzayev,
Macromolecules , 2009,
42 , 2135.
J. W. Andreasen, M. Jorgensen, and F. C. Krebs,
Macromolecules , 2007,
40 , 7758.
M. B. Runge and N. B. Bowden,
J. Am. Chem. Soc. , 2007,
129 , 10551.
P. J. Goodhew, J. Humphreys, and R. Beanland,
Electron Microscopy and Analysis , Taylor&Francis Inc., New York (2001).
Q. Zhang, D. R. Lippits, and S. Rastogi,
Macromolecules , 2006,
39 , 658.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
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OpenStax, Physical methods in chemistry and nano science. OpenStax CNX. May 05, 2015 Download for free at http://legacy.cnx.org/content/col10699/1.21
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