Masszi G, Inzelt G, Gróf P
Acta Biochim Biophys Acad Sci Hung. 1976;11(1):45-50.
Microwave conductivity and dielectric condstant of poly-(vinyl-alcohol) (PVA) solutions of 0--10 per cent were determined at 2--4 GHz frequency in the temperature range from 25 degrees C to 35 degrees C. The low-frequency conductivities of the solutions were measured at 20 kHz in the same concentration and temperature range. Microwave conductivity was proportional to the square of frequency, and the axial section extrapolated to zero frequency was higher than low-frequency conductivity. This difference in conductivity can probably be attributed to the relaxation processes of water molecules interacting directly with macromolecules. The relaxation wavelength calculated from the frequency dependence of microwave conductivity increased and the dielectric constant of the solutions decreased with increasing macromolecular concentration in a linear way. The activation energy calculated from its temperature dependence was 4.0 +/- 1.0 kcal/mol. The products of self-diffusion coefficient and macroviscosity were compared with that of self-diffusion coefficient and microviscosity calculated from relaxation wavelength. From this the conclusion can be drawn that the self-diffusion of water is influenced by the concentration dependent microviscosity. The hydration numbers calculated by different methods give divergen results the discussion of which requires further investigations.
在25摄氏度至35摄氏度的温度范围内，于2 - 4吉赫兹频率下测定了浓度为0 - 10%的聚乙烯醇（PVA）溶液的微波电导率和介电常数。在相同浓度和温度范围内，于20千赫兹测定了溶液的低频电导率。微波电导率与频率的平方成正比，外推至零频率的轴向截面高于低频电导率。这种电导率差异可能归因于与大分子直接相互作用的水分子的弛豫过程。由微波电导率的频率依赖性计算出的弛豫波长随大分子浓度的增加而增加，且溶液的介电常数呈线性下降。由其温度依赖性计算出的活化能为4.0±1.0千卡/摩尔。将自扩散系数与宏观粘度的乘积与由弛豫波长计算出的自扩散系数与微观粘度的乘积进行了比较。由此可以得出结论，水的自扩散受浓度依赖性微观粘度的影响。通过不同方法计算出的水合数给出了不同的结果，对此的讨论需要进一步研究。
