Abstract

Polarisation modulation infrared linear dichroism (PM-IRLD) is an infrared spectroscopy technique allowing the in situ study of the orientation dynamics at the 400 ms time scale. Strain-induced orientation and subsequent relaxation can be monitored for both blend components while the system returns to an isotropic state.

The poly (ethylene oxide) (PEO)/poly(4-hydroxystyrene) (PVPh) blend has strong specific intermolecular interactions in the form of hydrogen bonds. In as such, the system is completely miscible over all compositions under study. Miscibility has been asserted by differential scanning calorimetry: For a given blend composition, only one narrow glass transition could be detected.

Our PM-IRLD results show that PEO, which has the lowest glass transition temperature (T_g), orients much more than PVPh and remains more oriented even at the end of the experimental time. The incorporation of PEO causes the relaxation slowdown of both components. In PVPh-rich blends, orientational coupling is present while at higher PEO concentrations, the relaxation of both polymers is clearly uncorrelated.