Alessio Priscila, Ferreira Daniele M, Job Aldo E, Aroca Ricardo F, Riul Antonio, Constantino Carlos J L, Gonzalez Eduardo R Pérez
Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia, UNESP, Presidente Prudente/SP, 19060-080, Brazil.
Langmuir. 2008 May 6;24(9):4729-37. doi: 10.1021/la703328z. Epub 2008 Apr 10.
The synthesis of a poly(azo)urethane by fixing CO(2) in bis-epoxide followed by a polymerization reaction with an azodiamine is presented. Since isocyanate is not used in the process, it is termed "clean method" and the polymers obtained are named "NIPUs" (non-isocyanate polyurethanes). Langmuir films were formed at the air-water interface and were characterized by surface pressure vs mean molecular area per mer unit (Pi-A) isotherms. The Langmuir monolayers were further studied by running stability tests and cycles of compression/expansion (possible hysteresis) and by varying the compression speed of the monolayer formation, the subphase temperature, and the solvents used to prepare the spreading polymer solutions. The Langmuir-Blodgett (LB) technique was used to fabricate ultrathin films of a particular polymer (PAzoU). It is possible to grow homogeneous LB films of up to 15 layers as monitored using UV-vis absorption spectroscopy. Higher number of layers can be deposited when PAzoU is mixed with stearic acid, producing mixed LB films. Fourier transform infrared (FTIR) absorption spectroscopy and Raman scattering showed that the materials do not interact chemically in the mixed LB films. The atomic force microscopy (AFM) and micro-Raman technique (optical microscopy coupled to Raman spectrograph) revealed that mixed LB films present a phase separation distinguishable at micrometer or nanometer scale. Finally, mixed and neat LB films were successfully characterized using impedance spectroscopy at different temperatures, a property that may lead to future application as temperature sensors. Principal component analysis (PCA) was used to correlate the data.
介绍了一种通过在双环氧化合物中固定CO₂，然后与偶氮二胺进行聚合反应来合成聚（偶氮）聚氨酯的方法。由于该过程中未使用异氰酸酯，因此被称为“清洁方法”，所获得的聚合物被命名为“NIPUs”（非异氰酸酯聚氨酯）。在空气-水界面形成了Langmuir膜，并通过表面压力与每单体单元的平均分子面积（π-A）等温线进行表征。通过进行稳定性测试以及压缩/膨胀循环（可能存在滞后现象），并改变单分子层形成的压缩速度、亚相温度以及用于制备铺展聚合物溶液的溶剂，对Langmuir单分子层进行了进一步研究。使用Langmuir-Blodgett（LB）技术制备了特定聚合物（PAzoU）的超薄膜。使用紫外-可见吸收光谱监测发现，可以生长多达15层的均匀LB膜。当PAzoU与硬脂酸混合时，可以沉积更多层数，从而产生混合LB膜。傅里叶变换红外（FTIR）吸收光谱和拉曼散射表明，在混合LB膜中材料没有发生化学相互作用。原子力显微镜（AFM）和显微拉曼技术（与拉曼光谱仪耦合的光学显微镜）表明，混合LB膜在微米或纳米尺度上呈现出可区分的相分离。最后，使用阻抗光谱在不同温度下成功表征了混合和纯LB膜，这一特性可能会导致其在未来用作温度传感器。使用主成分分析（PCA）对数据进行关联。
