芘标记磺酸基聚电解质在水与DMSO中的荧光光谱

合成了芘标记单体N-(芘基)甲基-2-甲基丙烯酰胺(PyMA),其与2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、N,N-二甲基丙烯酰胺(DMAA)共聚,得到含PyMA摩尔分数为0.1%、AMPS摩尔分数F_AMPS分别为0.033～0.896的芘标记磺酸基聚电解质.在DMSO和水中,F_AMPS<0.449时芘标记聚电解质的荧光光谱与PyMA的荧光光谱基本相同;当F_AMPS≥0.449时,芘的0,1]和0,3]跃迁的发射强度大幅度增强.芘标记的I₁/I₃值随聚电解质电荷密度增加逐渐减小,且随聚电解质浓度增加也减小,表明聚电解质体系中通过电离基团间吸引形成了分子主链的聚集.

Fluorescence Spectra of Pyrene Labeled Polyelectrolytes with Sulfonate Groups in Water and DMSO

Pyrenylmethyl methacrylamide(PyMA) was synthesized, and applied to copolymerizing with AMPSand DMAAto get a series of pyrene labeled polymers with sulfonate groups. The molar fraction of sulfonate monomer AMPSin these samples varies from 0.0326 to 0.896 . In DMSOand water, the profile of fluorescence spectrum of pyrene labeled polyelectrolytes is analogous to that of PyMAwhen F_AMPS < 0.449, while the 0,1] emission peak abruptly increased as F_AMPS ≥0.449. The so called polarity scale of pyrene, I₁/ I3 of pyrene labeled polyelectrolytes in DMSOand in water decreases gradually with increasing F_AMPSrepresenting the charge density of the samples. I₁/ I3 also decreases gradually with the increase in polymer concentration in water. The results imply that there exists the hydrophobic aggregation through locally electrostatic attraction even in polyelectrolyte/polar solvent system, in contrast to the traditional polyelectrolyte theory. However, I₁/ I3 of these polyelectrolytes remains almost a constant with increasing NaCl concentration of aqueous solution up to 0.75 mol/L, indicating the electrostatic attraction cannot be simply screened.