Zero Thermal Expansion Fluid and Oriented Film Based on a Bistable Metal-Cyanide Polymer
Zero Thermal Expansion Fluid and Oriented Film Based on a Bistable Metal-Cyanide Polymer
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DOI：
10.1021/cm203762k
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发表时间：
2012-03
影响因子：
8.6
通讯作者：
H. Tokoro;Kosuke Nakagawa;K. Imoto;F. Hakoe;S. Ohkoshi
中科院分区：
文献类型：
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作者：
H. Tokoro;Kosuke Nakagawa;K. Imoto;F. Hakoe;S. Ohkoshi
以聚乙二醇单月桂酸酯（PEGM）为表面活性剂，制备了一种片状六氰合铁酸铷锰（Rb0.97Mn[Fe（CN）6]0.99·0.3H2O）零热膨胀（ZTE）材料。所制备的微晶显示出在立方MnII-NC-FeIII和四方MnIII-NC-FeII相之间的电荷转移诱导相变。MnIII-NC-FeII相在15 K - 300 K的宽温度范围内沿aLT和cLT轴沿着表现出小的负热膨胀（NTE），热膨胀系数为α（aLT）= −1.40 ± 0.12 × 10-6 K-1和α（cLT）= −0.17 ± 0.13 × 10-6 K-1。这样的小|α|材料被归类为中兴材料。远红外光谱表明，NTE源于304 cm-1附近的横平移模δ（Fe-C_CN-Mn）和253和503 cm-1处的横平移模δ（Fe-C_CN-Mn）。分子轨道计算表明，ZTE和电荷转移相变都是一个很好的过程。
A zero thermal expansion (ZTE) material based on plate-shaped rubidium manganese hexacyanoferrate, Rb0.97Mn[Fe(CN)6]0.99·0.3H2O, is prepared using a polyethylene glycol monolaurate (PEGM) surfactant matrix. The prepared microcrystals show a charge transfer induced phase transition between the cubic MnII–NC–FeIII and tetragonal MnIII–NC–FeII phases. The MnIII–NC–FeII phase exhibits a small negative thermal expansion (NTE) along the aLT and cLT axes with a thermal expansion coefficient of α(aLT) = −1.40 ± 0.12 × 10–6 K–1 and α(cLT) = −0.17 ± 0.13 × 10–6 K–1 over a wide temperature range of 15 K – 300 K. Such small |α| materials are classified as ZTE materials. The far-infrared spectra show that NTE originates from the transverse modes δ(Fe–C≡N–Mn)of the transverse translational mode around 304 cm–1, and transverse librational modes at 253 and 503 cm–1, which are assigned according to first principle calculations. Molecular orbital calculations indicate that ZTE and the charge transfer phase transition both ...