This set of Nanotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Nano Structured Material – Polymers”.
1. There are several factors affecting the size of polymeric nanocrystals. Which of the following is not one of them?
a) Temperature
b) Concentration
c) Surfactants
d) Humidity
View Answer
Explanation: The size of polymeric nanocrystals can be controlled by changing the temperature, concentration and also the mixing procedure. Surfactants also play a role in regulating the size. This is due to their property of modifying the surface of the particles or reducing surface tension of the solution.
2. Which polymers show the feature of electrical conductivity?
a) Block copolymers
b) Organic metals
c) Polystyrene
d) Bakelite
View Answer
Explanation: Organic metals are good conductors of electricity. They are commonly known as conductive polymers. Polyacetylene, Thiophenes are some examples of these polymers.
3. What property of dendralysts accounts for its easy isolation from a reaction mixture?
a) Large size
b) Solid state
c) Heterogeneous
d) Catalytic nature
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Explanation: Dendralysts are dendrimers that possess catalytic sites at their terminal groups. These molecules can be easily separated from a mixture after the reaction, owing to their large size. This would not have been possible if the dendrimer molecules were smaller or had solid polymer supports.
4. Which sequence is followed by the dendrimers of polyamidoamine during its divergent growth?
a) 2, 4, 8, 16 …
b) 3, 6, 12, 24 …
c) 3, 9, 27, 81 …
d) 5, 10, 20, 40 …
View Answer
Explanation: Polyamine grows in accordance with the series of 2, 4, 8, 16 …. Polyamidoamine on the other hand grows in accordance with the sequence 3, 6, 12, 24 … This continuous doubling growth is known as divergent growth and the process is referred to as divergent synthesis.
5. These two monomers have similar structures, but with a slight difference of sulphur atom replaced by a nitrogen atom bonded to hydrogen. Which pair represents these monomers?
a) Thiophene and Pyrrole
b) Thiophene and Pyridine
c) Pyrrole and Imidazole
d) Piperidine and Pyrrole
View Answer
Explanation: Thiophene and Pyrrole have similar structures. Thiophene has a molecular formula of (C4H4S) while the molecular formula for Pyrrole is (C4H4NH). These molecules have alternating double and single bonds in their structures and hence they form pi-conjugated polymers.
6. Nanoparticles of Chitosan, a natural polymeric material, have found a number of applications in the field of biomedical technology, owing to its advantageous behavior. Choose one option from the following that does not correspond to the advantages of Chitosan.
a) Low water solubility
b) Easily degradable
c) Anti – microbial
d) Innocuous
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Explanation: Chitosan nanoparticles are widely used in gene transfer, drug delivery, hydrogel and etc. Its nanoparticles exhibit biocompatibility, absorbability, and film formation. These features account for its wide usage in the medical field.
7. Polyaniline and its analogs are used in LEDs. Which properties of the polymer accounts for this application?
a) Electropositive and Electrophilic
b) Electronegative and Chemophilic
c) Electrochromic and Chemochromic
d) Electrophilic and Chemochromic
View Answer
Explanation: Polyaniline can change its color on application of particular voltage and suitable chemicals. So it is Electrochromic and Chemochromic. These properties make it useful for LEDs.
8. Performance of Chitosan derivatives is often better than Chitosan. Which process is not used in the synthesis of Chitosan derivatives?
a) Alkylation
b) Combustion
c) Sulphation
d) Quaternization
View Answer
Explanation: There are various processes used for the production of Chitosan derivatives. Acylation, Hydroxylation, Alkylation, Sulphation and Quaternization are some of those processes.
9. Which among the following is an aggregate of molecules with hydrophilic heads and hydrophobic tails, in aqueous solutions?
a) Vesicles
b) Dendralysts
c) Micelles
d) Globules
View Answer
Explanation: Micelle is a supra-molecular structure. It contains multiple molecules with hydrophobic tails (forming cluster on the inside) and hydrophilic heads pointing outwards to the enclosing aqueous medium.
10. Nanostructures of block copolymers have a lot of applications. Which of the following is not one of them?
a) Catalysts
b) Production of nanosized electronic devices
c) Semitransparent antistatic coating
d) Water reclamation
View Answer
Explanation: Block copolymers are used as catalysts, for water reclamation, and also in the production of electronic devices that are nanosized. These polymers provide a powerful tool for manipulating surface characteristics when they are self-assembled into micelles.
11. Why are nanoparticle based drugs preferred for therapeutic dosages over traditional drugs?
a) Biodegradable
b) High toxicity
c) Increased active constituent absorption
d) Sensitivity to salt ions
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Explanation: With the advancement of biomedical science, nanoparticle based drugs are slowly replacing traditional drugs. This is because of their active constituent absorption that significantly reduces the therapeutic dosage.
12. Biodegradable nanostructured polymers can be classified into artificial as well as natural polymers.
a) True
b) False
View Answer
Explanation: Biodegradable polymers can either be natural or artificial in nature. Some of the natural biodegradable polymers are nucleic acids, proteins and polysaccharides. Artificial biodegradable polymers include polyvinyl alcohol and polyamides.
13. Why is PHB (Poly-β-hydroxybutrate), a biosynthesized polymer widely used in suture surgery?
a) It has sustained hypoglycemic effect beyond 24 hours
b) It is a biosynthetic polymer
c) It is a high molecular polymer
d) It can degrade in vivo and hence does not require its removal after surgery
View Answer
Explanation: PHB being a biodegradable and biocompatible polymer is not only used as a drug delivery agent but also in tissue engineering as a scaffold material. Since it is biodegradable it does not require its removal after surgery and can degrade in vivo.
14. Why are AgNPs-chitosan nanoparticles more efficient in inhibiting the growth of E-coli compared to either of AgNPs or Chitosan alone?
a) They entrap drugs into their interior structure
b) They enhance the leakage of intracellular constituents and proteins from the bacterial cells
c) They have controlled release properties due to pH, temp and etc
d) They are chemically modified
View Answer
Explanation: The negatively charged surface of E-coli when attached to the positively charged Chitosan, it enhances the binding of AgNPs to proteins, present on cell wall. This leads to leakage of proteins and intra-cellular constituents of E-coli. This eventually destroys the bacteria.
15. Which of the following is an environment friendly preparation method of polymer nanoparticles?
a) Ultrasonication
b) Sol-gel method
c) Citrate method
d) Flame spray method
View Answer
Explanation: Flame spray synthesis, Sol-gel method, Citrate method are various processes of production of nano ceramics. Ultrasonication is an eco-friendly technique for production of nano polymers. This method is advantageous because it is non-toxic, produces extremely small particles and has rapid reaction rate.
Sanfoundry Global Education & Learning Series – Nanotechnology.
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