Nilsson Martin, Strømme Maria
Department of Engineering Sciences, The Angström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
J Phys Chem B. 2005 Mar 31;109(12):5450-5. doi: 10.1021/jp046991a.
The conduction mechanism in microcrystalline cellulose (MCC) tablets at varying relative humidity (RH) has been investigated by using the techniques of low frequency dielectric spectroscopy and transient current analysis at room temperature. The dependence on RH on the measured conductivity and charge carrier density indicates that a high-power-law-exponent percolation process of cations being conducted on water molecules occupying available 6-OH units on the cellulose chains is the dominating dc conduction mechanism at RH below 3 wt % of moisture content. The experimentally observed decrease in charge carrier mobility with increasing moisture content shows that protons and H3O+ ions that are being blocked at empty 6-OH sites also contribute to the charge transport process in cellulose at low moisture contents.
通过在室温下使用低频介电谱和瞬态电流分析技术，研究了微晶纤维素（MCC）片剂在不同相对湿度（RH）下的传导机制。对测得的电导率和电荷载流子密度对相对湿度的依赖性表明，在纤维素链上占据可用6-OH单元的水分子上进行阳离子传导的高幂律指数渗流过程是水分含量低于3 wt%时的主要直流传导机制。实验观察到电荷载流子迁移率随水分含量增加而降低，这表明在低水分含量下，在空的6-OH位点被阻断的质子和H3O+离子也对纤维素中的电荷传输过程有贡献。
