Mohammed Hawkar A, Mohammed Pshko A, Aziz Shujahadeen B
Department of Physics, College of Science, Charmo University Peshawa Street, Chamchamal 46023 Sulaimanyah Kurdistan Region Iraq
Turning Trash to Treasure Laboratory (TTTL), Research and Development Center, University of Sulaimani Qlyasan Street Sulaymaniyah 46001 Kurdistan Region Iraq
RSC Adv. 2025 Jul 7;15(29):23319-23341. doi: 10.1039/d5ra01881a. eCollection 2025 Jul 4.
In this study, PEO-based polymer composites with enhanced optical properties were fabricated by employing a green chemistry approach. A Mn(ii) metal complex was synthesized by combining dissolved manganese acetate with an extract of black tea (BT). Then, polymer composite films were prepared using a casting method, incorporating different concentrations of the Mn-polyphenol complex into the PEO matrix. Characterization of the Mn(ii) complex was carried out using XRD, FTIR, and UV-vis spectroscopy. The results demonstrated that black tea extract is an effective medium for synthesizing the Mn(ii)-polyphenol complex. FTIR analysis confirmed the formation of Mn-PPHNL complexes and their interaction with BT. XRD patterns indicated the amorphous nature of the Mn-polyphenol complex and showed that increasing the complex concentration led to a more amorphous PEO matrix, which was further analyzed using Urbach energy. Additionally, morphological analysis using an optical microscope (OM) image demonstrates that the size of the spherulites attributed to the crystalline phase drastically reduces as the concentration of Mn-polyphenol in a PEO polymer composite increases. UV-vis spectroscopy revealed key optical features, including optical density (), Urbach energy ( ), band gap ( ), and localized state density (/*). Various models, including Tauc's model, absorption edge, ASF, optical dielectric loss, Cody representation and differentiation (d/d, d/d, d/d) approaches, were used to identify the optical band gap of the films. Tauc's plots confirmed the nature of electronic transitions. Dielectric loss measurements indicated a reduction in the PEO bandgap from 5.5 eV to 1.4 eV upon metal complex incorporation. The ASF method further corroborated bandgap changes using only absorbance data. Metallization criteria were applied to classify the polymer's behavior as insulating or metallic. A redshift in absorption edge with increasing complex concentration, from 5.3 eV to 1.42 eV, confirmed the successful interaction between PEO and the metal complex, as validated by UV-vis spectroscopy.
在本研究中，采用绿色化学方法制备了具有增强光学性能的聚环氧乙烷（PEO）基聚合物复合材料。通过将溶解的醋酸锰与红茶（BT）提取物混合，合成了一种锰（II）金属配合物。然后，采用流延法制备聚合物复合薄膜，将不同浓度的锰 - 多酚配合物掺入PEO基体中。使用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和紫外 - 可见光谱对锰（II）配合物进行了表征。结果表明，红茶提取物是合成锰（II） - 多酚配合物的有效介质。FTIR分析证实了锰 - 多酚 - 茶黄素（PPHNL）配合物 的形成及其与BT的相互作用。XRD图谱表明锰 - 多酚配合物的非晶态性质，并表明配合物浓度的增加导致PEO基体更加非晶化，这通过乌尔巴赫能量进一步分析。此外，使用光学显微镜（OM）图像进行的形态分析表明，随着PEO聚合物复合材料中锰 - 多酚浓度的增加，归因于结晶相的球晶尺寸急剧减小。紫外 - 可见光谱揭示了关键的光学特征，包括光密度（）、乌尔巴赫能量（）、带隙（）和局域态密度（/*）。使用了各种模型，包括陶克（Tauc）模型、吸收边、ASF、光学介电损耗、科迪（Cody）表示和微分（d/d、d/d、d/d）方法来确定薄膜的光学带隙。陶克图证实了电子跃迁的性质。介电损耗测量表明，掺入金属配合物后，PEO的带隙从5.5电子伏特降至1.4电子伏特。ASF方法仅使用吸光度数据进一步证实了带隙变化。应用金属化标准将聚合物的行为分类为绝缘或金属。吸收边随着配合物浓度的增加发生红移，从5.3电子伏特到1.42电子伏特，证实了PEO与金属配合物之间的成功相互作用，这通过紫外 - 可见光谱得到验证。
