Problem 1: Discuss the length alternation of carbon-carbon bonds in trans-
polyacetylene. Compare this phenomenon with the bond lengths in benzene and
Problem 2: List the similarities and differences between the doping of silicon and the
doping of a conjugated polymer.
Problem 3: Draw the chemical structure of poly(1,4-phenylene vinylene) doped with
sulfuric acid (one HSO4° dopant for every two phenylenevinylene repeating units). Based
on the measured gravitational density of 1.4 grams/cm³ and electrical conductivity of 2.7
X 104 S/cm,
1. Calculate the doped polymer's macroscopic carrier mobility
2. How would you fabricate a conductive thin film based on this polymer.
Problem 4: Elaborate a method to turn a polyester clothing antistatic and thus more
comfortable to wear.
Problem 5: Draw the chemical structure of emeraldine base. Describe two approaches to
process conducting polymer fibers based on emeraldine base.
Problem 6: Based on your knowledge about the electrochemical redox of polypyirole,
predict the general features of the cyclic voltamogram of PPy doped with poly(styrene
sulfonate) in an aqueous solution of poly(styrene sulfonate tetraethylammonium, PSS
Problem 7: Devise a smart window that can be reversibly switched between dark
(absorbing blue and green portion of the sun light) and light blue (sky blue).
Problem 8: Devise a bimorph actuator based on two conducting polymers such that the
bimorph exhibits linear motion (expand/contract in length).
Problem 9: Water soluble conjugated polymers are being studied for biosensing. What
are the structural characteristics of such polymers? Explain why they may be superior to
laser dyes (fluorescent organic small molecules).
Problem10: Use the data from Lecture 5A, slide 3, calculate the transmittance of
polyaniline with a surface resistance of 100 ohm/square.
Problem11 Structure-property relationship is critically important in materials science.
Discuss four (4) structural aspects of conjugated polymers and how they may affect the
property of the polymer. Give one example for each structure-property relationship.
Problem 12 Compare Shirakawa polyacetylene and poly(1-(p-
butylphenyl)-2-phenylacetylene) with regard to (1) thin film
fabrication, (2) band gap, (3) conductivity of doped polymers, and (4)
fluorescence. Justify your answers.
Problem 13 Compared to poly(2-hexyl-1,4-phenylene), poly(9,9-dihexylfluorene-2,7-
diyl) has higher molecular weight and smaller bandgap. Explain the differences.
Problem 14 MEH-PPV is an orange light emitting polymer invented by Professor Fred
Wudl. It is widely used for polymer LEDs and solar cells. Describe how this polymer is
synthesized and how conjugation defects may be formed in the synthesis.
Problem 5What is solvatochromism? Would
you expect solvatochromism observed from the
two substituted polythiophenes shown to the
right? Do they behave similarly or differently?
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