二维红外光谱研究聚碳酸酯薄膜中水的扩散

利用二维衰减全反射红外光谱方法，研究了水在聚碳酸酯(PC)薄膜中的扩散过程，发现水的羟基弯曲振动谱带中可以分辨出分别位于1672、1646和1621 cm-1的吸收峰，而羟基伸缩振动谱带中可以分辨出分别位于3560、3425和3255 cm-1的吸收峰，由此可知水分子在聚碳酸酯薄膜中存在3种状态，分别为与羰基形成强、中强氢键作用的水分子和进入PC微孔中的弱氢键作用的水分子。 经过二维相关分析得到水分子进入PC薄膜的顺序为首先形成中等强度的氢键，然后形成弱和强2种强度的氢键。

Water Diffusion in Polycarbonate Film Studied by 2D FTIR Spectroscopy

The diffusion of water into polycarbonate film was investigated by attenuated total reflection Fourier transform infrared(ATR-FTIR) spectroscopy. Via band deconvolution in the O—H bending region, three components were identified, which were located at 1669, 1648 and 1623 cm-1, respectively, whereas in the O—H stretching region, three bands at 3562, 3423 and 3246 cm-1, respectively were isolated. These results indicate the presence of three states of water molecules in the polycarbonate matrix: strong, moderate, and weak hydrogen-bonded water. Two dimensional correlation analysis of the IR data further confirmed the presence of the three states, and revealed the sequence of the formation of the three types of hydrogen bonding. Based on these experimental results, we concluded that when water diffuses into polycarbonate matrix, it first forms moderate hydrogen bond with the carbonyl group(i.e. the water bound to the carbonyl), followed by the formation of strong hydrogen bonds due to a water molecule bridging a carbonyl and another carbonyl or water molecule, and weak hydrogen bond between water molecules in microvoids.