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Study on the Solution Properties of Thermo‐Responsive Polyrotaxanes with Different Numbers of Cyclic Molecules
Author(s) -
Ikeda Taichi,
Watabe Nobuyuki,
Ooya Tooru,
Yui Nobuhiko
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010501)202:8<1338::aid-macp1338>3.0.co;2-o
Subject(s) - copolymer , intermolecular force , polymer chemistry , ethylene glycol , materials science , dynamic light scattering , fluorescein isothiocyanate , molecule , chemistry , fluorescence , polymer , nanotechnology , organic chemistry , composite material , nanoparticle , physics , quantum mechanics
Polyrotaxanes, in which different numbers of β‐cyclodextrins (β‐CDs) were threaded on the triblock copolymer of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) capped with fluorescein‐4‐isothiocyanate (FITC), were prepared, and their solution properties under alkaline conditions were characterized in terms of the localization of β‐CDs on the triblock copolymer and intermolecular association. Below the critical association concentration (CAC), the location of the β‐CDs on the triblock copolymer was analyzed by 1 H NMR. It was confirmed that the majority of the β‐CDs moved towards the PPG segment with increasing temperature, regardless of the number of threading β‐CDs. Above CAC, intermolecular association of the polyrotaxanes was characterized by static light scattering measurements. The association number of the polyrotaxanes decreased with increasing the number of the threading β‐CDs, and the temperature dependence on the association number was reduced with increasing the number of the threading β‐CDs. It is considered that the threading of β‐CDs on the triblock copolymer eliminates the intermolecular interaction. These findings suggest that the number of β‐CDs in the polyrotaxanes is a key parameter for the solution properties of the thermo‐responsive polyrotaxanes.