Thermosensitive poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer, Pluronic F68, containing a hydrophobic unit, oligo-(lactic acid)(oligo-LA) or oligo-caprolactone (oligo-CL), 2-META and RGD as side groups was successfully synthesized and characterized by 1H NMR, FTIR, and elemental analysis. Their aqueous solution displayed special gel-sol-gel phase transition behavior with increasing temperature from 10 to 70°C, when the polymer concentration was above critical micelle concentration (CMC). The gel-sol phase diagram was investigated using tube inversion method, rheological measurement, and dynamic light scattering. Based on these results, the gelation properties of modified F68 were affected by several factors such as the composition of the substituents, chain length of oligo l-LA or oligo -CL, and the concentration of the polymer solutions. The unique phase transition behavior with temperature was observed by modified F68 triblock copolymer, composed of the PPO blocks core and the PEO blocks shell in aqueous solution. This phenomenon was elucidated using 1H NMR data; the alteration of hydrophobic interaction and chain mobility led to the formation of transparent gel, coexistence of gel-sol, and opaque gel. These hydrogels may be useful in drug delivery and tissue engineering.
Bibliographical noteFunding Information:
This research was supported by Pioneer Research Center Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (2010-0002170), and a grant from the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy, Republic of Korea (K00060-282).
- Biodegradable polymer
- Gel-sol transition
- Pluronic F68
- RGD peptide
- Thermosensitive hydrogel
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry