Salt effect on the phase transition behavior of thermo-sensitive polyamide

Abstract

Phase transition behavior and influence of ions on the thermo-sensitive polyamide with polyethylene glycol as the main chain were studied in detail. By measuring the light transmission rates of polymer solutions, the change of its lower critical solution temperature (LCST) in the salt solution was investigated. It was found that a reversible phase transition of the polyamide occurred at the LCST and finished in a narrow temperature range. The LCST was associated with species of ions in salt solution. Anions had a great impact on the phase transition performance of the thermo-sensitive polyamide, while the cations had a slight influence on the phase transition. Different anions had different coagulation ability to ‘salt-out’ the polyamide. The order was: CO₃ ²⁻>SiO₃ ²⁻>HPO₄ ²⁻>OH⁻>Cl⁻>HCO³⁻>HSO³⁻>NO²⁻>NO³⁻.

Keywords

temperature-sensitive polymer / critical solution temperature / salt effect / phase transition behavior

References

[1] Schild H.G. Poly(N-isopropylacrylamide): Experiment, Theory and Application[J]. Prog. Polym. Sci., 1992, 17: l63-249.

[2] Graziano G. On the Temperature Induced Coil to Globule Transi-tion of Poly-N-isopropylacrylamide in Dilute Aqueous Solu-tions[J]. Int. J. Biol. Macromol., 2000, 27(1): 89-97.

[3] Suzuki A., Tanaka T. Phase Teansition in Polymer Gels Induced by Visible Light[J]. Nature, 1990, 346(26): 345-347.

[4] Bekturov E.A., Fromova V.A., Bimendina L.A. Swelling Behaviour of a Non-ionic Poly(N-vinyl-2-pyrrolidone) Gel in a Linear Poly(acrylic acid) solution[J]. Macromol. Chem. Phys., 1999, 200(2): 431-435.

[5] Takashi A., Yayoi N., Kohei S. e. a1. Glucose-sensitive Lower Critical Solution Temperature Changes of Copolynlers Composed of N-isopropylacrylamide and Phenylboronic Acid Moieties[J]. Polymer J., 1996, 28(4): 371-374.

[6] Boude C., Iliopoulos I., Monti F. e. a1. Smart Reactivity in Gelatine/PNIPAM Mixtures: Control of the Cross-Linking and Micro-heterogeneities[J]. Macromo1. Symp., 2006, 239(1): 114-119.

[7] Zhang J.T., Huang S.W., Cheng S. e. a1. Preparation and Properties of Poly(N-isopropylacrylamide)/ Poly(N-isopropylacrylamide) Interpenetrating Polymer Networks for Drug Delivery[J]. Polym. Sci. Part A: Polym. Chem., 2004, 42(5): 1 249-1 254.

[8] Zhou L., Lu Z.Y., Zhang X., . The Studies on the Temperature Sensitive of N-isopropylacrylamide Copolymer[J]. Polymer Materials Science and Engineering, 2006, 22(2): 165-168.

[9] Elena K., Yachin C., Havazelet B.P. The Effect of Salts on the Conformation and Microstructure of Poly (N-isopropylacrylamide) in Aqueous Solution[J]. Polym. Sci: Part B: polym. Phys., 2004, 42(20): 3 713-3 720.

[10] Rackaitis M., Strawhecker K., Manias E. Water-soluble Polymers with Tunable Temperature Sensitivity:Solution Behavior[J]. Polym. Sci.: Part B: Polym.Phys., 2002, 40: 2 339-2 342.

[11] Park T.G., Hoffman A.S. Sodium Chloride-induced Phase Transition in Nonionic Poly (N -isopropy-lacrylamide) Gel[J]. Macro-molecules, 1993, 26(19): 5045-5048.

[12] Bailey F.E., Callard R.W. Some Properties of Poly(ethylene oxide) in Aqueous Solution[J]. Appl. Polym.Sci., 1959, 1: (56-62).

[13] Bian F.L., Liu M.Z. The Influence of Additives on Thermosensitivity of Poly(N,N-diethylacrylamide)[J]. Journal of Lanzhou University (Natural Sciences), 2003, 39(1): 54

[14] Wang M.Z., Gao L.N. Salt Effect on the Phase Transition Behavior of Poly (N-isopropylacrylamide)[J]. Journal of Shaanxi Normal University (Natural Science Edition), 2000, 28(3): 84

[15] Chen Z.Q., Dai M.G. Colloidal chemistry[M], 1985 Beijing Geological Publishing House