Thermoresponsive Phase Transitions of PLA-block-PEO-block-PLA Triblock Stereo-Copolymers in Aqueous Solution

Hyung Tak Lee; Doo Sung Lee

Macromolecular Research, Vol.10, No.6, 359-364, December, 2002

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Thermoresponsive Phase Transitions of PLA-block-PEO-block-PLA Triblock Stereo-Copolymers in Aqueous Solution

Hyung Tak Lee, and Doo Sung Lee^†

Center for Advanced Functional Polymers, Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon, Kyungki 440-746, Korea

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A series of PLA-PEO-PLA triblock stereo-copolymers with varying PLA/PEO and L-/DL-LA ratios were synthesized via ring opening polymerizations. Aqueous solutions of these copolymers undergo thermo-responsive phase transitions as the temperature monotonically increases. Further study shows that there is a critical gel concentration (CGC), and also lower and upper critical gel temperatures (CGTs), at which the thermo-responsive phase transition occurs. The CGC and CGTs are affected by various factors such as block length, as well as the compositions of the PLA blocks and of the additives. In particular, the changes in the phase diagram produced by varying the L-/DL-LA ratio in the PLA blocks were determined to be mainly due to consequent stereo-regularity changes in the PLA blocks.

Keywords:biodegradable;thermo-responsive;phase transition;triblock stereo-copolymer

[References]

Chen GH, Hoffman AS, Nature, 373(6509), 49 (1995)
Yoshida R, Uchida K, Kaneko Y, Sakai K, Kikuchi A, Sakurai Y, Okano T, Nature, 374(6519), 240 (1995)
Guenet JM, Thermoreversible Gelationof Polymers and Biopolymers, Academic Press, New York (1992)
Yang Z, Pickard S, Deng NJ, Barlow RJ, Attwood D, Booth C, Macromolecules, 27(9), 2371 (1994)
Yang YW, Yang Z, Zhou ZK, Attwood D, Booth C, Macromolecules, 29(2), 670 (1996)
Malmsten M, Lindman B, Macromolecules, 25, 5446 (1992)
Wout Z, Pec EA, Maggiore JA, J. Parenteral Sci. Technol., 46(6), 192 (1992)
Palmer WK, Emeson EE, Johston TP, Atherosclerosis, 136, 115 (1998)
Suh H, Jeong BM, Rathi R, Kim SW, J. Biomed. Mater. Res., 42(2), 331 (1998)
Jeong B, Bae YH, Lee DS, Kim SW, Nature, 388(6645), 860 (1997)
Leong BM, Lee DS, Shon JI, Bae YH, Kim SW, J. Polym. Sci. A: Polym. Chem., 37(6), 751 (1999)
Jeong B, Bae YH, Kim SW, Macromolecules, 32(21), 7064 (1999)
Choi SW, Choi SY, Jeong B, Kim SW, Lee DS, J. Polym. Sci. A: Polym. Chem., 37(13), 2207 (1999)
Bae YH, Huh KM, Kim YG, Park KH, J. Control. Release, 64, 3 (2000)
Huh KM, Bae YH, Polymer, 40(22), 6147 (1999)
Li YX, Christian V, Kissel T, J. Control. Release, 32, 121 (1994)
Sung YK, Kim SW, Korea Polym. J., 8(5), 199 (2000)
Lee JW, Hua F, Lee DS, J. Control. Release, 73, 315 (2001)
Shim MS, Kim SW, Lee HJ, Chang T, Lee DS, Macromol. Rapid Commun., 22, 587 (2001)
Shim MS, Lee HT, Shim WS, Park IS, Lee HJ, Chang TH, Kim SW, Lee DS, J. Biomed. Mater. Res., 61(2), 188 (2002)
Molina I, Li S, Martinez MB, Vert M, Biomaterials, 22, 363 (2001)
Zaslavsky BY, Aqueous Two Phase Partitioning, Marcel Dekker, New York (1995)
Finch CA, Chemistry and Technology of Water-Soluble Polymers, Plenum Press, New York (1983)

[Referenced By]

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[1] Chen GH, Hoffman AS, Nature, 373(6509), 49 (1995)

[2] Yoshida R, Uchida K, Kaneko Y, Sakai K, Kikuchi A, Sakurai Y, Okano T, Nature, 374(6519), 240 (1995)

[3] Guenet JM, Thermoreversible Gelationof Polymers and Biopolymers, Academic Press, New York (1992)

[4] Yang Z, Pickard S, Deng NJ, Barlow RJ, Attwood D, Booth C, Macromolecules, 27(9), 2371 (1994)

[5] Yang YW, Yang Z, Zhou ZK, Attwood D, Booth C, Macromolecules, 29(2), 670 (1996)

[6] Malmsten M, Lindman B, Macromolecules, 25, 5446 (1992)

[7] Wout Z, Pec EA, Maggiore JA, J. Parenteral Sci. Technol., 46(6), 192 (1992)

[8] Palmer WK, Emeson EE, Johston TP, Atherosclerosis, 136, 115 (1998)

[9] Suh H, Jeong BM, Rathi R, Kim SW, J. Biomed. Mater. Res., 42(2), 331 (1998)

[10] Jeong B, Bae YH, Lee DS, Kim SW, Nature, 388(6645), 860 (1997)

[11] Leong BM, Lee DS, Shon JI, Bae YH, Kim SW, J. Polym. Sci. A: Polym. Chem., 37(6), 751 (1999)

[12] Jeong B, Bae YH, Kim SW, Macromolecules, 32(21), 7064 (1999)

[13] Choi SW, Choi SY, Jeong B, Kim SW, Lee DS, J. Polym. Sci. A: Polym. Chem., 37(13), 2207 (1999)

[14] Bae YH, Huh KM, Kim YG, Park KH, J. Control. Release, 64, 3 (2000)

[15] Huh KM, Bae YH, Polymer, 40(22), 6147 (1999)

[16] Li YX, Christian V, Kissel T, J. Control. Release, 32, 121 (1994)

[17] Sung YK, Kim SW, Korea Polym. J., 8(5), 199 (2000)

[18] Lee JW, Hua F, Lee DS, J. Control. Release, 73, 315 (2001)

[19] Shim MS, Kim SW, Lee HJ, Chang T, Lee DS, Macromol. Rapid Commun., 22, 587 (2001)

[20] Shim MS, Lee HT, Shim WS, Park IS, Lee HJ, Chang TH, Kim SW, Lee DS, J. Biomed. Mater. Res., 61(2), 188 (2002)

[21] Molina I, Li S, Martinez MB, Vert M, Biomaterials, 22, 363 (2001)

[22] Zaslavsky BY, Aqueous Two Phase Partitioning, Marcel Dekker, New York (1995)

[23] Finch CA, Chemistry and Technology of Water-Soluble Polymers, Plenum Press, New York (1983)