Thoma Janine L, Little Hunter, Duhamel Jean, Zhang Lei, Leung Kam Tong
Institute for Polymer Research, Waterloo Institute for Nanotechnology, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Waterloo Institute for Nanotechnology, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Polymers (Basel). 2023 Sep 30;15(19):3958. doi: 10.3390/polym15193958.
Seven pyrene-labeled poly(oligo(ethylene glycol) methyl ether methacrylate)s (PyEG-PEGMAs) were prepared with = 0, 3, 4, 5, 7, 9, and 19 ethylene glycol units by copolymerizing a small amount of penta(ethylene glycol) 1-pyrenemethyl ether methacrylate with an EGMA monomer. The conformation of the PyEG-PEGMA polymers evolved from a random coil for PyEG-PEGMA or poly(methyl methacrylate) to a polymeric bottle brush (PBB) architecture with increasing side chain length. The fluorescence decays of the PyEG-PEGMA samples were fitted according to the fluorescence blob model (FBM) whose parameters were used, in combination with the Kratky-Porod equation, to calculate the persistence length of these polymers. The persistence lengths obtained from the PEF experiments were found to increase with the square of the number () of non-hydrogen atoms in the side chain as expected theoretically. The persistence lengths found with the PyEG-PEGMA samples in DMF also matched those found earlier for another series of PEGMA samples labeled with 1-pyrenebutanol. The good agreement found between the persistence lengths obtained with the PEGMA samples labeled with two different pyrene derivatives illustrates the robustness of the method and its applicability for measuring the unknown persistence length of polydisperse polymer samples.
通过将少量的1-芘甲基醚甲基丙烯酸五乙二醇酯与甲基丙烯酸乙二醇酯单体共聚，制备了七种芘标记的聚（聚乙二醇甲醚甲基丙烯酸酯）（PyEG-PEGMAs），其乙二醇单元数分别为0、3、4、5、7、9和19。随着侧链长度增加，PyEG-PEGMA聚合物的构象从PyEG-PEGMA或聚甲基丙烯酸甲酯的无规线团演变为聚合物刷（PBB）结构。根据荧光斑点模型（FBM）对PyEG-PEGMA样品的荧光衰减进行拟合，其参数与Kratky-Porod方程结合使用，以计算这些聚合物的持久长度。从PEF实验获得的持久长度发现，如理论预期那样，随侧链中非氢原子数（）的平方增加。在DMF中PyEG-PEGMA样品发现的持久长度也与先前用1-芘丁醇标记的另一系列PEGMA样品发现的持久长度相匹配。用两种不同芘衍生物标记的PEGMA样品获得的持久长度之间的良好一致性说明了该方法的稳健性及其在测量多分散聚合物样品未知持久长度方面的适用性。
