Investigation of polystyrene-b-polyisoprene using broadband dielectric spectroscopy

David Brian Noirat & Rasmus Kristoffer Pedersen

Studenteropgave: Kandidatprojekt


In this project, the normal and segmental relaxation modes of the diblock copolymer polystyrene-block-polyisoprene was investigated by the means of broadband dielectric spectroscopy. The relaxation of two samples in laminar phase was investigated and compared with the relaxation of the neat polymers and of a macroscopic mixture of the neat polymers.
Dielectric spectroscopy was done at temperatures ranging from the glass transition temperature of polyisoprene to room temperature, 190-305 K, and frequencies ranging from 10^{-2} Hz to 10^6 Hz.

Measurements of the neat polymers were analysed and found to be in agreement with literature.
As an additional investigation, flash freezing of the temperature driven disordered state of the diblock was carried out. Unfortunately an unidentified source of conduction obscured the results of all experiments, making a complete analysis of this experiment impossible.
Investigation of the macroscopic mixture of the two neat polymers yielded results similar to neat polyisoprene.
The relaxation modes for polyisoprene were found to exhibit a slowing down in the diblock copolymer compared to neat polyisoprene, as found in a similar study Jenczyk et al. 2010. Due to a low signal-to-noise ratio, significant data was only obtainable for one diblock copolymer, but similar findings would be expected to be found for the other.

UddannelserFysik, (Bachelor/kandidatuddannelse) Kandidat
VejledereKristine Niss