Structure of Water in the Vicinity of Amphoteric Polymers as Revealed by Vibrational Spectroscopy
Structure of Water in the Vicinity of Amphoteric Polymers as Revealed by Vibrational Spectroscopy
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DOI：
10.1163/092050610x488278
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发表时间：
2010-01
期刊：
影响因子：
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通讯作者：
H. Kitano;Makoto Gemmei-Ide
中科院分区：
文献类型：
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作者：
H. Kitano;Makoto Gemmei-Ide
用红外光谱中O-H伸缩的谱带形状分析了由不同比例的甲基丙烯酸(MA)、N-[3-(二甲氨基)丙基]甲基丙烯酰胺(DMAPMA)和甲基丙烯酸丁酯组成的两性三元共聚物薄膜中的水。在水吸附到聚合物膜的早期阶段，膜中含有相对含量的MA和DMAPMA残基的水的O-H伸缩带与主体水相似。这些结果清楚地表明，阳离子和阴离子基团含量相当的两性聚合物不会显著干扰水的氢键网络结构，这可能是由于阴离子和阳离子侧基之间的接近而抵消了静电水合效应。在所考察的三元共聚物膜中，MA和DMAPMA残基含量相当的膜上附着的血小板数量相对最少，这表明电荷平衡聚合物材料对包合水结构的温和程度与其血液相容性有关。此外，还利用偏光拉曼光谱中的O-H伸缩等值线分析了不同配比的MA、[3-(methacryloylamino)propyl]trimethylammonium和MAPTAC组成的共聚物水溶液中水的结构和氢键。由于PolyMA中一个单体残基的存在而破坏的氢键数量(N corr值)基本上为正，随着DMAPMA或MAPTAC残基含量的增加，N corr值变小，在大致等摩尔比通过最小值(仍略为正值)后，N corr值再次增加。这与均聚物(PolyMA、PolyDMAPMA和PolyMAPTAC)以及其他普通聚电解质的大体上为正的N Corr值形成了显著的对比。拉曼光谱观察到的电荷平衡共聚物对附近水中氢键网络结构的影响与红外光谱观察到的电荷平衡型三元共聚物膜的影响是一致的。
The water incorporated in a thin film of amphoteric terpolymers composed of various ratios of methacrylic acid (MA), N-[3-(dimethylamino)propyl]methacrylamide (DMAPMA) and n-butyl methacrylate was analyzed using the band shapes of the O–H stretching in the infrared spectra. At an early stage of sorption of water into the polymer film, the O–H stretching band for the water incorporated in the film with comparative contents of MA and DMAPMA residues was similar to that for bulk water. These results clearly indicate that the amphoteric polymers with comparative contents of cationic and anionic groups do not significantly disturb the hydrogen-bonded network structure of water, probably due to the counteraction of the electrostatic hydration effect by the proximity between the anionic and cationic side groups. The number of platelets adhered to the film with comparative contents of MA and DMAPMA residues was relatively the smallest among the examined terpolymer films, which suggested a correlation between the mildness of the charge-balanced polymeric materials to the structure of incorporated water and their blood-compatibilities. In addition, the structure and hydrogen bonding of water in an aqueous solution of co-polymers composed of various ratios of MA and DMAPMA or [3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) were also analyzed using the contours of the O–H stretching in the polarized Raman spectra. The number of hydrogen bonds disrupted due to the presence of one monomer residue (N corr value) for PolyMA was largely positive, and with an increase in the content of the DMAPMA or MAPTAC residues, the N corr value became smaller, and after passing a minimum (which was still slightly positive) at a roughly equivalent molar ratio, the N corr value increased again. This is in a significant contrast with the largely positive N corr values for the homo-polymers (PolyMA, PolyDMAPMA and PolyMAPTAC), and other ordinary polyelectrolytes. The effect of the charge-balanced co-polymer on the hydrogen-bonded network structure of vicinal water observed by Raman spectroscopy was in accordance with that of the charge-balanced terpolymer film observed by infrared spectroscopy.