Synthesis of High Refractive Index Polymer Thin Films for Soft, Flexible Optics Through Halomethane Quaternization of Poly(4‐Vinylpyridine)
Synthesis of High Refractive Index Polymer Thin Films for Soft, Flexible Optics Through Halomethane Quaternization of Poly(4‐Vinylpyridine)
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聚（4-乙烯基吡啶）卤代甲烷季铵化制备高折射率柔性光学薄膜
DOI：
10.1002/adom.202302201
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发表时间：
2024-01
影响因子：
9
通讯作者：
Ni Huo;Jeremy Rivkin;Ruobin Jia;Yineng Zhao;W. Tenhaeff
中科院分区：
文献类型：
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作者：
Ni Huo;Jeremy Rivkin;Ruobin Jia;Yineng Zhao;W. Tenhaeff
在柔软、柔性的光学和光电应用中的应用要求聚合物薄膜涂层能够适应大量的物理变形。本文报道了用（二）卤代甲烷季铵化聚（4-乙烯基吡啶）（P4 VP）薄膜制备高折射率聚合物（HRIPs）的方法。通过引发化学气相沉积（iCVD）制备P4 VP薄膜，然后通过暴露于碘甲烷（CH 3 I）、二溴甲烷（CH 2Br 2）和二碘甲烷（CH 2 I2）的饱和蒸气进行季铵化，导致折射率（RI）分别高达1.67、1.71和2.07（在632.8 nm处）。傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）证实了聚合物链上的吡啶侧基主要与碘化物或溴化物抗衡而季铵化为N-甲基吡啶鎓，尽管也检测到小部分的多碘化物。此外，这些膜表现出上级热稳定性，在热偏移至200 °C后保持其折射率和厚度。卤化的P4 VP膜表现出上级的机械灵活性相对于传统的无机涂层（Al 2 O 3和Ta 2 O 5），并不断裂，在单轴拉伸应变高达10%。这种新的材料化学和制造方法可以在广泛的衬底和器件架构中实现先进的光学设计和功能。
Applications in soft, flexible optical, and optoelectronic applications demand polymer thin film coatings that can accommodate substantial physical deformations. The preparation of high refractive index polymers (HRIPs) through the quaternization of poly(4‐vinylpyridine) (P4VP) thin films with (di)halomethanes is presented. P4VP thin films are prepared by initiated chemical vapor deposition (iCVD) and then quaternized through exposure to saturated vapors of iodomethane (CH3I), dibromomethane (CH2Br2), and diiodomethane (CH2I2), resulting in refractive indices (RI) as high as 1.67, 1.71, and 2.07, respectively (at 632.8 nm). Fourier‐transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS) confirmed the quaternization of pyridine pendant groups on the polymer chain to n‐methylpyridinium with primarily an iodide or bromide counterion, though a minor fraction of polyiodides are also detected. Additionally, these films demonstrate superior thermal stability, retaining their refractive index and thickness after thermal excursions to 200 °C. The halogenated P4VP films exhibit superior mechanical flexibility relative to conventional inorganic coatings (Al2O3 and Ta2O5) and do not fracture at uniaxial tensile strains as high as 10%. This new material chemistry and fabrication approach method may enable advanced optical designs and functionality in a wide range of substrates and device architectures.