Question 1 (a) Characterize polymers chitosan (CHI) and polyacrylic acid (PAA) into those generating polycations/polyanions, weak/strong, syntheticatural, rigid/coiled. Explain your answer, provide chemical structures of the polymers and estimate their pKa. (i) Provide the chemical structures for the repeating units of the polymers chitosan (CHI) and polyacrylic acid (PAA) and estimate their pKa. (3 marks) (ii) Characterize each polymer as the following and provide an explanation for your answers: - generating polycations or polyanions, - weak or strong polyelectrolyte - synthetic or natural - rigid or coiled (4 marks) (b) Calculate the mass of CHI and PAA (in mg ) needed to form ( CHI/PAA)2 multilayer capsules using 106 polystyrene beads (the bead diameter is 20m ) in 0.1MNaCl at 42C. The thickness of the multilayer shell is 2m. Assume that the multilayers are formed at the polymer mass ratio 1:1 and the capsule shell density is 1kgdm3. (7 marks) (c) Formation of the CHI/PAA complexes in NaCl at an ionic strength 0.1M and a temperature of 37C was investigated. Below are the reaction of the complex formation and the value of equilibrium constant for the complex formation (K): Chi0+PAA+2H+Chi(PAA)H2+,log(K)=22.10.5 Calculate Gibbs free energy and the entropy of the decomposition of the CHI/PAA complex if the enthalpy of its decomposition (H) is 15.0kJmol1. (10 marks) (d) Describe the mechanism of encapsulation into multilayer capsules through temperature mediated annealing process. Provide schematics in your answer. (6 marks)