Albu Raluca Marinica, Stoica Iuliana, Nica Simona Luminita, Soroceanu Marius, Barzic Andreea Irina
"Petru Poni" Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania.
Polymers (Basel). 2024 Nov 26;16(23):3288. doi: 10.3390/polym16233288.
Optical filters are essential components for a variety of applicative fields, such as communications, chemical analysis and optical signal processing. This article describes the preparation and characterization of a new optical filter made of polyvinyl alcohol and incremental amounts of crystal violet. By using distinct solvents (HO, dimethyl sulfoxide (DMSO) and HO) to obtain the dyed polymer films, new insights were gained into the pathway that underlies the possibility of tailoring the material's optical performance. The effect of the dye content on the sample's main properties was inspected via UV-VIS spectroscopy analysis combined with colorimetry, refractometry and atomic force microscopy experiments. The results revealed that the colorimetric parameters are affected by the dye amount and are dramatically changed when the solvent used for film preparation is different. The rise in the refractive index upon polymer dyeing was due to the synergistic effect of the larger polarizability of the dye and the occurrence of hydrogen bonds among the system components. Spectral data evidenced that samples prepared in HO and DMSO preserve the absorption characteristics of the added dye, whereas HO acts as an oxidizing agent and enhances transparency. Also, for the first two solvents, multiple absorption edges were noted as a result of dye incorporation, which was responsible for the occurrence of new exciton-like states, hence the band gap reduction. The films processed in HO were able to block radiations in the 506-633 nm range while allowing other wavelengths to pass with a transmittance above 90%. The samples attained in DMSO presented similar properties, with the difference that the domain of light attenuation was shifted towards higher wavelengths. Atomic force microscopy showed the dye's effect on the level of surface roughness uniformity and morphology isotropy. The dyed polymer foils in non-oxidizing agents have suitable features for use as band-pass filters.
光学滤波器是通信、化学分析和光信号处理等多种应用领域的关键组件。本文描述了一种由聚乙烯醇和增量结晶紫制成的新型光学滤波器的制备与表征。通过使用不同的溶剂（水、二甲基亚砜（DMSO）和水）来获得染色聚合物薄膜，对定制材料光学性能可能性背后的途径有了新的认识。通过紫外可见光谱分析结合比色法、折射法和原子力显微镜实验，研究了染料含量对样品主要性能的影响。结果表明，比色参数受染料用量影响，且当用于制备薄膜的溶剂不同时会发生显著变化。聚合物染色后折射率的升高是由于染料较大的极化率与体系组分间氢键的形成产生的协同效应。光谱数据表明，在水和DMSO中制备的样品保留了添加染料的吸收特性，而水起到氧化剂的作用并提高了透明度。此外，对于前两种溶剂，由于染料掺入出现了多个吸收边，这导致了新的类激子态的出现，从而使带隙减小。在水中处理的薄膜能够阻挡506 - 633 nm范围内的辐射，同时允许其他波长以高于90%的透过率通过。在DMSO中获得的样品呈现出类似的性质，不同之处在于光衰减范围向更高波长移动。原子力显微镜显示了染料对表面粗糙度均匀性和形态各向同性水平的影响。在非氧化剂中染色的聚合物箔片具有适合用作带通滤波器的特性。
