title: Characterization of the spontaneously forming hydrogels composed of water-soluble phospholipid polymers.
abstract: Spontaneously forming hydrogels composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers, poly(MPC-co-methacrylic acid) (PMA), and poly(MPC-co-n-butyl methacrylate) (PMB) were examined. The MPC copolymer hydrogel was observed to have a spontaneous gelation property. To determine the properties of the hydrogels and why the gelation takes place, we have studied the properties of the hydrogels by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The morphologies of the hydrogels were spongelike with a homogeneous structure. By XPS analysis in terms of the molecular distributions in the hydrogels, it was observed that a stabilization time was required for the hydrogel to undergo chain rearrangement. DSC thermograms of the hydrogels were different from their components, PMA and PMB. For the hydrogel, a crystallization peak around -30 degrees C was observed. This result indicated that some ordered structures existed in the hydrogels. To determine the role of the MPC groups, aqueous solutions of poly(methacrylic acid) (PMAc) and PMB were mixed. The mixture of PMAc-PMB turned into a sol state, and the sol state remained for a week. When the mixture was cooled, a very weak hydrogel was prepared. This result suggested that the MPC groups were the dominant unit for spontaneously forming the hydrogels.
authors.affiliation: Department of Materials Science, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Kwang Woo
authors.initials: KW
authors.lastname: Nam
authors.forename: Junji
authors.initials: J
authors.lastname: Watanabe
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D008567:Membranes, Artificial; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010743:Phospholipids / Q000138:chemical synthesis*; D011108:Polymers / Q000138:chemical synthesis*; D013052:Spectrometry, X-Ray Emission; D014867:Water / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D008567:Membranes, Artificial; D008689:Methacrylates; D010743:Phospholipids; D011108:Polymers; D014867:Water