Influence of graft interface polarity on hydration/dehydration of grafted thermoresponsive polymer brushes and steroid separation using all-aqueous chromatography
Influence of graft interface polarity on hydration/dehydration of grafted thermoresponsive polymer brushes and steroid separation using all-aqueous chromatography
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DOI：
10.1021/la801949w
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发表时间：
2008-10-07
期刊：
影响因子：
3.9
通讯作者：
Okano, Teruo
中科院分区：
文献类型：
--
作者：
Nagase, Kenichi;Kobayashi, Jun;Okano, Teruo
我们通过表面引发原子转移自由基聚合（ATRP）制备了具有不同温度响应性疏水性能的聚（N-异丙基丙烯酰胺）（PIPAAm）刷接枝表面。这些温度响应表面的特点是通过色谱分析，使用改性的二氧化硅珠作为色谱固定相在水移动的相。在SiO2微球表面形成了由ATRP引发剂和不同末端官能团的硅烷组成的混合硅烷自组装单分子膜。然后使用CuCl/CuCl 2/Me 6 TREN催化剂体系在2-丙醇中于25 ℃通过ATRP聚合IPAAm 16小时。类固醇的色谱保留行为上得到的PIPAAm刷上更极性的硅烷组分是不同的，从更非极性的硅烷接口。类固醇的PIPAAm混合非极性硅烷接枝接口的保留时间显着长于那些类似的极性硅烷接口，由于非极性硅烷接枝表面上的PIPAAm刷增强脱水。保留因子的变化，K，极性硅烷PIPAAm接枝的接口上相对较大的非极性PIPAAm接枝的接口相比，由于较大的水合/脱水改变接枝PIPAAm刷前表面。从50到10摄氏度的应用步骤温度梯度表明，极性硅烷界面上的PIPAAm刷倾向于水合更多，导致更短的保留时间。总之，接枝界面的极性显著影响接枝PIPAAm刷的水合/脱水特性，随后也影响全水色谱中生物活性化合物的温度调节分离。
We have prepared poly(N-isopropylacrylamide) (PIPAAm) brush-grafted surfaces with varied temperature-responsive hydrophobic properties through surface-initiated atom transfer radical polymerization (ATRP). These temperature-responsive surfaces were characterized by chromatographic analysis using modified silica beads as a chromatographic stationary phase in aqueous mobile phase. Mixed silane self-assembled monolayers (SAMs) comprising ATRP initiator and silanes with various terminal functional groups were formed on the silica bead Surfaces. IPAAm was then polymerized by ATRP using the CuCl/CuCl2/Me6TREN catalyst system in 2-propanol at 25 degrees C for 16 h. The chromatographic retention behavior of steroids on the resulting PIPAAm brushes made on more polar silane components was distinct from that on more apolar silane interfaces. Retention times for steroids on PIPAAm mixed apolar silane graft interfaces were significantly longer than those on analogous polar silane interfaces due to enhanced dehydration of PIPAAm brushes on apolar silane-grafted surfaces. Changes in retention factor, K, on polar silane PIPAAm-grafted interfaces were relatively large compared to that on apolar PIPAAm grafted interfaces due to larger hydration/dehydration alterations of grafted PIPAAm brushes on the former surfaces. Applied step-temperature gradients from 50 to 10 degrees C show that PIPAAm brushes on polar silane interfaces tend to hydrate more, leading to shorter retention times. In conclusion, the polarity of the grafted interface significantly influences the grafted PIPAAm brush hydration/dehydration characteristics and subsequently also the temperature-modulated separation of bioactive compounds in all-aqueous chromatography.