Question

Polymer chains adopt different conformations in solutions. The size of a polymer chain can be described by the mean end-to-end distance (mean thread end spacing) and by the radius of gyration.

a) Name the physical cause of why polymer chains adopt different conformations. Outline how the solvent affects the conformation and thus the size of the polymer chains. What is the parameter of the solvent that influences the size of polymer chains in a solvent?

b) Describe the concept of the Kuhn chain and explain how this concept can be exploited for describing the rigidity of a polymer chain.

Answer 1

a) polymer chains adopt different conformations due to their hydrophobic part and hydrophillic part xue to these interaction they adopt different conformation. In solvent as the conformation depends on the type of solvent as the solvent which is more attractive towards the polymer chain causes the elongation of the chain and hence increases the length while the solvent which have lesser interaction with polymer chain causes the polymer to occupy the chain lesser surface area (like a gobule structure) hence decreases the end to end distance of polymer chain.

b) Kuhn chain or Kuhn segment is a theoretical treatment of polymer chain in which a straight segment of fixed size is consider irrespective of the number of actual monomers present in that segment to calculate the end to end distance as it describe the end to end distance hence give or describe tge rigidity of tge system and give the net distance between two ends rather than the actual distance between the monomers.