Dipartimento di Fisica, Universita' di Roma La Sapienza, Piazzale A. Moro 2, I-00185 Rome, Italy.
J Phys Chem B. 2010 Jun 3;114(21):7140-7. doi: 10.1021/jp100593z.
The concentration dependence of the dielectric properties of aqueous solutions of sodium maleate copolymers with comonomers of different hydrophobicities have been investigated by means of frequency domain dielectric spectroscopy in the frequency range from 1 kHz to 2 GHz. The dielectric relaxation falling between the process at low frequencies (polarization involving the whole polymer chain) and the one at high frequencies (polarization of the bulk aqueous phase) has been analyzed in light of the scaling properties of polyelectrolyte solutions. Within this framework, the dielectric properties are governed by two characteristic lengths, the distance R(cm) between chains in the dilute regime and the correlation length xi in the semidilute regime. We find that, for both these regimes, the exponents of the scaling laws, which describe the dielectric increment Deltaepsilon and the relaxation time tau(ion) are in a reasonably good agreement with the ones experimentally observed. This analysis gives further support to the scaling approach of the dynamic behavior of polyelectrolytes, appearing very suitable to modeling our dielectric results.
采用频率域介电谱法，在 1 kHz 至 2 GHz 的频率范围内，研究了具有不同疏水性单体的马来酸钠共聚物水溶液的介电性质随浓度的变化关系。根据聚电解质溶液的标度性质，分析了低频（涉及整个聚合物链的极化）和高频（水相的整体极化）之间的介电弛豫。在这个框架内，介电性质由两个特征长度决定，即稀相中链之间的距离 R（cm）和半稀相中相关长度 xi。我们发现，对于这两个区域，描述介电增量 Deltaepsilon 和弛豫时间 tau(ion)的标度律的指数与实验观察到的指数非常吻合。这种分析为聚电解质动态行为的标度方法提供了进一步的支持，这种方法非常适合模拟我们的介电结果。
