Heat capacity and index of refraction of polyzwitterions
Heat capacity and index of refraction of polyzwitterions
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DOI：
10.1016/j.polymer.2022.125176
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发表时间：
2022-07
期刊：
影响因子：
4.6
通讯作者：
Andrew Clark;M. Rosenbaum;Yajnaseni Biswas;A. Asatekin;P. Cebe
中科院分区：
文献类型：
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作者：
Andrew Clark;M. Rosenbaum;Yajnaseni Biswas;A. Asatekin;P. Cebe
比热容和折射率测量了一系列的六个磺基甜菜碱两性离子聚合物，并比较拓扑和基团贡献模型。通过改变聚合物的化学结构，合成了聚磺基甜菜碱甲基丙烯酸酯（PSBMA）、聚磺基甜菜碱丙烯酸酯（PSBA）、聚乙基磺基甜菜碱甲基丙烯酸酯（PESBMA）、聚磺基甜菜碱甲基丙烯酰胺（PSBMAm）、聚磺基甜菜碱2-乙烯基吡啶（PSB 2 VP）和聚磺基甜菜碱4-乙烯基吡啶（PSB 4VP），研究了聚合物主链和侧基对其性能的影响。使用温度调制差示扫描量热法（TMDSC）以及准等温TMDSC来确定30 ° C至200 °C的温度依赖性比热容cp（T）。测量了所有聚两性离子的固态比热容，而液态比热容测量仅限于PSBA和PESBMA。采用波长为300 ~ 3000 nm的椭偏法测量了室温下聚两性离子薄膜的折射率。用拓扑和基团贡献法计算了聚两性离子的cp和n的理论室温值，并与实测值进行了比较。测量的折射率值与预测的聚两性离子。然而，对于固态热容，该模型仅对PSB 2 VP和PSB 4VP产生准确的预测。测量和预测的CP值之间的差异是最有可能的，由于物理交联的一些聚两性离子在固态中的运动的振动度的减少。
Specific heat capacities and indices of refraction were measured for a series of six sulfobetaine zwitterionic polymers and compared to topological and group contribution models. Poly(sulfobetaine methacrylate) (PSBMA), poly(sulfobetaine acrylate) (PSBA), poly(ethyl sulfobetaine methacrylate) (PESBMA), poly(sulfobetaine methacrylamide) (PSBMAm), poly(sulfobetaine 2-vinylpyridine) (PSB2VP) and poly(sulfobetaine 4-vinylpyridine) (PSB4VP) were specially synthesized with changes of chemical structure in order to study effects of either the polymer backbone or the side group on their properties. Temperature modulated differential scanning calorimetry (TMDSC) as well as quasi-isothermal TMDSC were used to determine the temperature dependent specific heat capacity, cp(T) from 30 to 200 °C. The solid state specific heat capacities were measured for all the polyzwitterions, while liquid state heat capacity measurements were limited to PSBA and PESBMA. Ellipsometry at wavelengths from 300 nm to 3000 nm was used to measure the index of refraction for polyzwitterion thin films at room temperature. Theoretical room temperature values of cpand n were calculated for the polyzwitterions using topological and group contribution methods and compared to the measured values. The measured index of refraction values agree well with predictions for the polyzwitterions. However, for the solid state heat capacity, the model produces accurate prediction only for PSB2VP and PSB4VP. The discrepancy between the measured and predicted cpvalues is most likely due to the reduction of vibrational degrees of motion in the solid state for some of the polyzwitterions due to physical crosslinking.