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用光子相关光谱测定了苯乙烯-二乙烯基苯(St-DVB)共聚超微粒在良溶剂(甲苯)与θ溶剂(环己烷)中不同温度下的分子扩散系数,与流体力学方程结合给出了该微粒在无限稀时的等效流体力学半径。微粒分子扩散与温度的关系符合Arrhenius方程。不同温度的测试结果表明,St-DVB共聚超微粒的微交联网络结构使其分子形态不易改变。在θ溶剂中,T<θ时,微粒发生聚集,表现出大分子的协同扩散;T>θ时,在较高浓度,扩散系数偏离与浓度的线性关系。流体力学作用和热运动决定了微粒分子的扩散行为。
The molecular diffusion coefficients of styrene-divinylbenzene (St-DVB) copolymeric particles at different temperatures in good solvents (toluene) and theta solvents (cyclohexane) were measured by photon correlation spectroscopy and combined with the hydrodynamic equations The equivalent hydrodynamic radius of the particle at infinity is given. The relationship between particle molecular diffusion and temperature accords with Arrhenius equation. The results of different temperatures show that the micro-crosslinked network structure of St-DVB copolymerized particles can not easily change its molecular morphology. In θ solvent, when T <θ, the particles aggregated to show the synergistic diffusion of macromolecules; at T> θ, at higher concentration, the linear relationship between the diffusion coefficient and the concentration deviated. Hydrodynamics and thermal motion determine the diffusion behavior of microparticle molecules.