College of Chemistry , Beijing Normal University , Beijing 100875 , China.
Langmuir. 2018 May 15;34(19):5574-5580. doi: 10.1021/acs.langmuir.8b00776. Epub 2018 May 4.
Dielectric spectroscopy can be applied to study the structure and dynamics of block polymer. In this work, dielectric measurements of block copolymer Pluronic L64 solution are carried out in the frequency range between 40 Hz and 110 MHz with variable temperatures and concentrations. We analyze the phase behavior of the PEO-PPO-PEO (Pluronic L64) aqueous system according to the concentration/temperature-dependence of direct current conductivity. The result indicates the sensitivity of the phase behavior and conductivity of the Pluronic L64 solution to temperature. Besides, two relaxations were observed: relaxation 1 (0.5 MHz) is related to the gelation process, while relaxation 2 (5 MHz) is caused by the interface polarization. On the basis of relaxation 2, the volume fraction and permittivity of the particle were calculated. The formations of the block copolymer micelle and gel are monitored successfully by the temperature/concentration-dependence of the dielectric parameters and the volume fraction.
介电谱可用于研究嵌段聚合物的结构和动力学。在这项工作中，在 40 Hz 至 110 MHz 的频率范围内，通过改变温度和浓度，对嵌段共聚物 Pluronic L64 溶液进行了介电测量。我们根据直流电导率的浓度/温度依赖性，分析了 PEO-PPO-PEO（Pluronic L64）水溶液的相行为。结果表明，Pluronic L64 溶液的相行为和电导率对温度敏感。此外，观察到两种弛豫：弛豫 1（0.5 MHz）与凝胶化过程有关，而弛豫 2（5 MHz）是由界面极化引起的。基于弛豫 2，计算了粒子的体积分数和介电常数。通过介电参数和体积分数的温度/浓度依赖性，成功地监测了嵌段共聚物胶束和凝胶的形成。
