Optimizing the Grafting Density of Tethered Chains to Alter the Local Glass Transition Temperature of Polystyrene near Silica Substrates: The Advantage of Mushrooms over Brushes
Optimizing the Grafting Density of Tethered Chains to Alter the Local Glass Transition Temperature of Polystyrene near Silica Substrates: The Advantage of Mushrooms over Brushes
复制标题
优化系链的接枝密度以改变二氧化硅基材附近聚苯乙烯的局部玻璃化转变温度：蘑菇相对于刷子的优势
DOI：
10.1021/acsmacrolett.8b00019
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发表时间：
2018
影响因子：
7.015
通讯作者：
Roth, Connie B.
中科院分区：
文献类型：
--
作者：
Huang, Xinru;Roth, Connie B.
我们使用荧光测量了聚苯乙烯（PS）的局部玻璃化转变温度（g(z)）作为与末端接枝链的二氧化硅衬底距离的函数，其中避免了自由表面的竞争效应，仅关注系结界面的影响。在最佳接枝密度下，链接底物附近的局部tg (z)相对于体积最大增加了49±2 K，对应于蘑菇到刷子的过渡状态。观察到这种对基体局部tg (z)动力学的扰动在恢复体积tg之前持续到最佳接枝密度≈100-125 nm，这一距离与Baglay和Roth先前观察到的距离相当[J]。化学。高分子学报，2017,46,203307]。
We measured the local glass transition temperatureTg(z) of polystyrene (PS) as a function of distancezfrom a silica substrate with end-grafted chains using fluorescence, where competing effects from the free surface have been avoided to focus only on the influence of the tethered interface. The localTg(z) increase next to the chain-grafted substrate is found to exhibit a maximum increase of 49 ± 2 K relative to bulk at an optimum grafting density that corresponds to the mushroom-to-brush transition regime. This perturbation to the localTg(z) dynamics of the matrix is observed to persist out to a distancez≈ 100–125 nm for this optimum grafting density before bulkTgis recovered, a distance comparable to that previously observed by Baglay and Roth [J. Chem. Phys.2017,146, 203307] for PS next to the higher-Tgpolymer polysulfone.