TY  - JOUR
AU  - Kang, Jia-Jhen
AU  - Shehu, Kaltrina
AU  - Sachse, Clemens
AU  - Jung, Florian A.
AU  - Ko, Chia-Hsin
AU  - Barnsley, Lester C.
AU  - Jordan, Rainer
AU  - Papadakis, Christine M.
TI  - A molecular brush with thermoresponsive poly(2-ethyl-2-oxazoline) side chains: a structural investigation
JO  - Colloid & polymer science
VL  - 299
SN  - 1435-1536
CY  - Heidelberg
PB  - Springer
M1  - FZJ-2020-02772
SP  - 193–203
PY  - 2021
AB  - The thermoresponsive behavior of a poly(2-oxazoline)-based molecular brush is investigated in aqueous solution. The molecular brush under study, PiPOx100-g-PEtOx17, has a poly(2-isopropenyl-2-oxazoline) (PiPOx) backbone grafted with thermoresponsive poly(2-ethyl-2-oxazoline) (PEtOx) side chains. Since the backbone degree of polymerization is only a factor of ~ 6 higher than the ones of the side chains, it features an architecture between a star-like polymer and a comb-like polymer. Its aqueous solution exhibits lower critical solution temperature (LCST) behavior with a cloud point temperature Tcp = 40.5 °C at 30 g L−1. The temperature-dependent structural evolution is disclosed using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). An increase of the molecular brush size is found upon heating from room temperature to Tcp, which is attributed to the extension of the backbone resulting from the dehydration and collapse of the side chains. Above Tcp, the size decreases again, which indicates the collapse of the whole molecular brush. Large aggregates are found to be present in the solution in the temperature range 25–50 °C. These become more compact, as the temperature is increased across Tcp.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000556215600001
DO  - DOI:10.1007/s00396-020-04704-6
UR  - https://juser.fz-juelich.de/record/878315
ER  -