Wang Xiangshuo, Shi Ling, Zhang Junying, Cheng Jue, Wang Xiaodong
Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
State Key Laboratory of Organic-Inorganic Composite Materials, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
R Soc Open Sci. 2018 Jan 17;5(1):170732. doi: 10.1098/rsos.170732. eCollection 2018 Jan.
This paper reports a new route to synthesize calcium carbonate (CaCO)-based nanoscale ionic materials (NIMs) via an formation method to form the CaCO nanoparticles with a polysiloxane quaternary ammonium salt (PQAC) corona (PQAC-CaCO nanoparticles), followed by an ionic exchange reaction to fabricate a poly(ethylene glycol)-tailed sulfonate anion (NPEP) canopy. The chemical compositions and structures of the CaCO-based NIMs synthesized in this work were confirmed by Fourier-transform infrared spectroscopy and solid-state C NMR spectroscopy. Transmission electron microscopic observation indicated that the CaCO-based NIMs presented a rhombohedral shape with a well-defined core-shell structure, and they also obtained an NPEP canopy with a thickness of 4-6 nm. X-ray powder diffraction investigation confirmed that the CaCO inner core had a calcite crystalline structure, whereas the NPEP canopy was amorphous. The NPEP canopy was found to show a characteristic crystallization-melting behaviour in the presence of the ion bonding with PQAC-CaCO nanoparticles according to the characterization of differential scanning calorimetry. Thermogravimetric analysis indicated that the CaCO-based NIMs achieved a high content of NPEP canopy as well as an improvement in thermal stability owing to the ion-bonding effect. Most of all, the CaCO-based NIMs demonstrated a liquid-like behaviour above the critical temperature in the absence of solvent. Moreover, the CaCO-based NIMs also showed a relatively high electrical conductivity with a temperature dependency due to the ionic conductive effect. This work will provide a more feasible and energy-saving methodology for the preparation of CaCO-based NIMs to promote their industrialization and extensive applications.
本文报道了一种合成碳酸钙（CaCO）基纳米级离子材料（NIMs）的新途径，即通过一种形成方法制备具有聚硅氧烷季铵盐（PQAC）冠层的CaCO纳米颗粒（PQAC-CaCO纳米颗粒），然后通过离子交换反应制备带有聚乙二醇尾端的磺酸根阴离子（NPEP）冠层。通过傅里叶变换红外光谱和固态碳核磁共振光谱对本工作中合成的CaCO基NIMs的化学成分和结构进行了确认。透射电子显微镜观察表明，CaCO基NIMs呈现菱面体形状，具有明确的核壳结构，并且还获得了厚度为4 - 6纳米的NPEP冠层。X射线粉末衍射研究证实，CaCO内核具有方解石晶体结构，而NPEP冠层是无定形的。根据差示扫描量热法的表征发现，NPEP冠层在与PQAC-CaCO纳米颗粒存在离子键合时表现出特征性的结晶-熔融行为。热重分析表明，由于离子键合作用，CaCO基NIMs实现了高含量的NPEP冠层以及热稳定性的提高。最重要的是，CaCO基NIMs在无溶剂条件下高于临界温度时表现出类似液体的行为。此外，由于离子导电效应，CaCO基NIMs还表现出相对较高的电导率且与温度相关。这项工作将为制备CaCO基NIMs提供一种更可行且节能的方法，以促进其工业化和广泛应用。
