Aggregation and Polymerization of PEG-Based Macromonomers with Methacryloyl Group as the Only Hydrophobic Segment.
Aggregation behavior in aqueous solution of a series of poly (ethylene glycol) (PEG)-based macromonomers with methacryloyl group as the only hydrophobic segment has been investigated using surface tension, steady-state and time-resolved fluorescence spectroscopy using pyrene as a probe, and small-angle neutron scattering techniques. The general formula of these macromonomers is CH(2)&dbond;C(CH(3))-CO-O-E(m)-CH(3), where E is the ethylene glycol unit and m=8 (ME(8)), 18 (ME(18)), 49 (ME(49)), and 120 (ME(120)). The results indicate that a macromonomer with 8 ethylene glycol units forms as an aggregate above a certain critical concentration, which can be defined as critical aggregation concentration. The observed high value of I(1)/I(3) in pyrene emission spectra at the interface of these aggregates and the inability to scatter a neutron beam by these aggregates indicate that the hydrophobic cluster formed by this macromonomer is remarkably solvated. ME(18) has a tendency to aggregate but others do not form any hydrophobic cluster. The homopolymerization behaviors of these macromonomers in an aqueous medium at 70 degrees C are consistent with these possibi- lities. Copyright 2001 Academic Press.
Maiti
Souvik
S
Speciality Polymer Group, OCP Division, Indian Institute of Chemical Technology, Hyderabad, 500007, India
Chatterji
Prabha R.
PR
Nisha
C. K.
CK
Manorama
S. V.
SV
Aswal
Vinod K.
VK
Goyal
Prem S.
PS