芘荧光探针法研究海藻酸钠与SDS的作用

Interaction between sodium alginate and sodium dodecyl sulfate probed by pyrene fluorescence

采用芘荧光法研究了海藻酸钠(NaAlg)与十二烷基硫酸钠(SDS)在不同pH水溶液中的相互作用。以芘单体的荧光光谱第一峰与第三峰的荧光强度之比(I1/I3)及激基缔合物与单体荧光强度之比(IE/IM)来探测芘分子所处环境的极性。结果表明:NaAlg水溶液随pH值降低,出现了聚合物的疏水微区;pH从7降到5,NaAlg类似简单盐,对SDS的临界胶束浓度(CMC)有明显的影响;在pH3时,海藻酸主链上有足够的疏水片段,使得SDS与海藻酸通过疏水性作用而聚集。NaCl对NaAlg/SDS体系的影响亦较明显。

Interactions between the sodium alginate（NaAlg） and the sodium dodecyl sulfate（SDS） at different pH values have been investigated by Pyrene Fluorescence methods.Micropolarity studies,using the emission intensity ratio between the first and third bands（I1/I3） and the intensity ratio of the excimer and the third vibration monomer band（IE/IM）,shows as the pH value decreases a larger number of polymeric hydrophobic microdomains will be present in the NaAlg aqueous solutions,and NaAlg polymers have an obvious effect on the CMC of SDS as a simple salt with the pH value of the solution decreaseing from 7 to 5. At the pH 3 there are enough the hydrophobic segments in the alginate chains and the aggregation between SDS and alginate due to hydrophobic interactions is observed. The effect of.salt （NaCI） added to NaAlg/SDS systemis obvious.