Question

15. When a dilute solution of block copolymers undergoes micellization, i.e., some numbers of chains aggregate into a (usually spherical) assembly to shield one block from the solvent it does not like, the light scattering intensity increases. In fact, if micellization is induced by changing temperature at a fixed concentration, the ratio of the intensity after micellization to that before micellization is a good estimate of the average aggregation number of the micelles. Explain this observation.

Answer 1

When a dilute solution of block copolymers undergoes micellization some numbers of chain aggregates into a assembly shields one block from the solvent , the light intensity increases.

But when micellization is induced by changing temperature at a fixed concentration, the ratio of intensity after micellization has a good estimate of average aggregate number of the micelles  than before micellization.

Temperature affects the rate of micellization. As the temperature of system increases , the micellization firstly decreases for some Time and then increases. The probability of making hydrogen bond becomes smaller at higher temperatures and for occuring the micellization In this condition, the higher concentration is needed. Due to all this the micelle particle aggregates much faster at higher temperature and intensity is also affected.