Wang Ying, Meng Zihao, Luo Zhenyang, Song Zhiqiang, Du Bo, Zhang Yongsheng, Ye Pengjin, Li Linling, He Yucheng, Sha Ye
Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
DingLi New Material Technology Co., Ltd., Taizhou 317022, China.
ACS Macro Lett. 2024 Nov 19;13(11):1584-1590. doi: 10.1021/acsmacrolett.4c00640. Epub 2024 Nov 7.
The conformational studies of polymers confined at the nanoscale remain challenging and controversial due to the limitations of characterization techniques. In this study, we utilized the high sensitivity of time-resolved fluorescence resonance energy transfer (FRET) and a site-specific dye-labeling strategy to characterize the conformation of polymer chains confined in anodic aluminum oxide (AAO) nanopores. This strategy introduced a fluorescent donor (carbazole) and acceptor (anthracene) at the center of poly(butyl methacrylate) (PBMA) chains grown by atom transfer radical polymerization (ATRP). By quantitatively analyzing fluorescence decay through the Förster mechanism and the Drake-Klafter-Levitz (DKL) formalism, we can determine both the energy transfer efficiency and the spatial distribution of the dyes. This analysis revealed that the PBMA chains, with a molecular weight of 40 kDa, maintained their bulk-like conformation even when confined within nanopores as small as 10 nm in diameter. This study is the first to demonstrate the use of FRET for investigating chain conformation in confined polymer systems, which can be generalized to other polymer types and polymer topologies in different confined geometries.
由于表征技术的局限性，对纳米尺度受限聚合物的构象研究仍然具有挑战性且存在争议。在本研究中，我们利用时间分辨荧光共振能量转移（FRET）的高灵敏度和位点特异性染料标记策略来表征阳极氧化铝（AAO）纳米孔中受限聚合物链的构象。该策略在通过原子转移自由基聚合（ATRP）生长的聚甲基丙烯酸丁酯（PBMA）链的中心引入了荧光供体（咔唑）和受体（蒽）。通过福斯特机制和德雷克 - 克拉夫特 - 莱维茨（DKL）形式定量分析荧光衰减，我们可以确定能量转移效率和染料的空间分布。该分析表明，分子量为40 kDa的PBMA链即使被限制在直径小至10 nm的纳米孔中，仍保持其本体状构象。本研究首次证明了使用FRET研究受限聚合物体系中的链构象，这可以推广到不同受限几何形状中的其他聚合物类型和聚合物拓扑结构。
