Structure and dynamics of supramolecules investigated by contrast variation neutron scattering

Endo, Hitoshi

Polyrataxane (PR) is a new category of supermolecular assemblies in which a linear polymer (polyethylene glycol(PEG)) penetrates a few hundreds ring molecules (-cyclodextrin (CD)) and the axial polymer is terminally-modified with sterically-bulky compounds in order not to allow the ring molecules to escape from the string. We have investigated the structure and dynamics of PR by means of contrast variation small-angle neutron scattering (SANS) and contrast variation neutron spin echo (NSE) experiments. With neutrons as probe, contrast variation techniques based on hydrogen/deuterium replacement can be used to modify the visibility of different component in the system. In order to study the properties of CD threaded into PEG, partially deuterated CD and PEG were synthesized for the preparation of PR with protonated CD and deuterated PEG (CD visible) and PR with deuterated CD and protonated PEG (PEG visible). SANS and NSE experiments were performed for these two materials and additional fully protonated PR, then the obtained scattering intensities were decomposed into the partial scattering functions for each components. The detailed analyses of each partial scattering function led to reveal the structure and dynamics of CD and PEG in PR with nanoscopic temporal-spatial resolution.