-
解决方案
-
SFM300应用资料4
发布:华洋科仪浏览次数:322A poly(glycerol monomethacrylate)-block-poly(2-(dimethylamino)ethyl methacrylate)-blockpoly( 2-(diethylamino)ethyl methacrylate) (GMA-DMA-DEA) triblock copolymer was synthesized via atom transfer radical polymerization (ATRP). The pH-induced micellization kinetics of this GMA-DMA-DEA triblock copolymer was investigated by employing a stopped-flow light scattering technique. Upon jumping from pH 4 to around 7-7.5, stopped-flow experiments revealed two distinct relaxation processes. The first relaxation mode had a positive amplitude, suggesting that the micelle size and/or micelle number density increases; in contrast, the second relaxation mode had a negative amplitude, which is assigned to the micelle formation-breakup process. However, upon jumping from pH 4 to pH >8, only relaxation processes with positive amplitude were observed. The relaxation curve can be well fitted with a doubleexponential function, leading to a fast relaxation time constant (ô1) and a slow relaxation time constant (ô2). ô1 is in the range 10-20 ms, which decreases with increasing polymer concentration. ô2 is around 110 ms, which is independent of concentration in the range studied. In the fast process (ô1), quick association of unimers into small micelles and fusion between small micelles result in the birth of quasiequilibrium micelles (with aggregation number per micelle still lower than that of equilibrium micelles) by consuming large amounts of excess unimers; the unimer concentration is close to the critical micellization concentration (cmc) at the end point of the fast process. 快速动力学停流装置与光谱分析系统
2012-12-12相关仪器 -
免责声明
①本网刊载上述内容,并不代表本网赞同其观点或证实其内容的真实性,不承担此类作品侵权行为的直接责任及连带责任
②若本站内容侵犯到您的合法权益,请及时告诉,我们马上修改或删除。邮箱:hezou_yiqi