Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/41241
標題: FTIR-ATR measurements of the ionization extent of acrylic acid within copolymerized methacrylated dextran/acrylic acid networks and its relation with pH/salt concentration-induced equilibrium swelling
作者: Chiu, H.C.
邱信程
Hsiue, T.
Chen, W.Y.
關鍵字: dextran hydrogels
dorman equilibrium theory
counterion condensation
sensitive dextran hydrogels
glycidyl methacrylate
controlled-release
enzymatic degradation
model protein
ph
salt
gels
behavior
drugs
期刊/報告no:: Polymer, Volume 45, Issue 5, Page(s) 1627-1636.
摘要: In this study, dextran hydrogels were obtained by free radical copolymerization of methacrylated dextran with acrylic acid (AAc) in aqueous solution. The fractions of dissociation of AAc units within hydrogel in response to changes in pH and ionic strength of external aqueous solution were determined by FTIR-ATR spectroscopy. The influence of small ion concentration within hydrogel on the dissociation constant of AAc follows the Debye-Huckel behavior. Based on the results from the FTIR-ATR measurements, the total ion concentration difference inside and outside the hydrogel was determined according to the Donnan equilibrium theory, taking account of the counterion condensation effect quantitatively. The swelling response of hydrogels to changes in external pH and ionic strength was governed mainly by the ionic osmotic pressure due to the accumulation of diffusible ions within hydrogels. The energy balance between the osmotic and elastic retractile responses indicates the non-Gaussian behavior of elastically effective subchains with increasing swelling. (C) 2003 Elsevier Ltd. All rights reserved.
URI: http://hdl.handle.net/11455/41241
ISSN: 0032-3861
文章連結: http://dx.doi.org/10.1016/j.polymer.2003.12.043
Appears in Collections:化學工程學系所

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