Interfacial Junctions Control Electrolyte Transport Through Charge-Patterned Membranes.
Interfacial Junctions Control Electrolyte Transport Through Charge-Patterned Membranes.
复制标题
界面连接控制电解质通过电荷模式膜的传输。
作者：
Feng Gao;A. Hunter;Siyi Qu;J. R. Hoffman;P. Gao;W. Phillip
不同的传输机制出现时，纳米结构的基板与多种化学图案。例如，电荷图案化的镶嵌膜具有用正电荷和负电荷的离散域官能化的表面。这些带相反电荷的结构域为溶解盐中的阳离子和阴离子渗透穿过膜提供了途径，而不会违反电中性的宏观约束。在这里，通过系统地改变电荷模式的几何形状和大小，我们阐明了分子间的相互作用，促进盐的运输下的压力驱动流的作用。对于由带正电荷和带负电荷的域的等效面积覆盖率组成的图案，几何参数的影响被封装在单个变量中，即界面堆积密度，其量化了由带相反电荷的域之间的结覆盖的膜表面的分数。在实验上，对称电解质（即，KCl和MgSO4）随着界面堆积密度的值而增加，而界面堆积密度不影响不对称电解质的传输（即，K2SO4和MgCl2）。膜表面附近的电势的模拟表明，对于对称的电解质，结构电荷的异质性降低了离子分配的障碍，从而促进盐通过膜的运输。对于不对称电解质，电荷不均匀性使离子的局部可用性偏离盐的化学计量比，从而阻碍盐传输。这些研究结果表明，通过膜的化学图案化，可以在各种化学分离和传感应用中找到实用性的运输机制的承诺。
Distinct transport mechanisms emerge when nanostructured substrates are patterned with multiple chemistries. For example, charge-patterned mosaic membranes possess surfaces functionalized with discrete domains of both positive and negative charge. These oppositely-charged domains provide pathways for both the cation and anion from a dissolved salt to permeate through the membrane without violating the macroscopic constraint of electroneutrality. Here, by systematically varying the geometry and size of the charge pattern, we elucidate the molecular interactions that promote the transport of salts under the action of pressure-driven flow. For patterns that consist of equivalent areal coverages of positively-charged and negatively-charged domains, the effects of the geometric parameters were encapsulated in a single variable, the interfacial packing density, that quantified the fraction of the membrane surface covered by junctions between oppositely-charged domains. Experimentally, the transport of symmetric electrolytes ( i.e., KCl and MgSO4) increased with the value of the interfacial packing density, while the interfacial packing density did not affect the transport of asymmetric electrolytes ( i.e., K2SO4 and MgCl2). Simulations of the electrical potential near the membrane surface demonstrate that for symmetric electrolytes, the structural charge heterogeneity reduces the barrier to ion partitioning thereby promoting salt transport through the membranes. For asymmetric electrolytes, the charge heterogeneity skews the local availability of ions from the stoichiometric ratio of the salt thus hindering salt transport. These findings demonstrate the promise of accessing transport mechanisms, which could find utility in a diverse range of chemical separations and sensing applications, through chemical-patterning of membranes.
影响因子：
16.6
作者：
Shen YX;Song W;Barden DR;Ren T;Lang C;Feroz H;Henderson CB;Saboe PO;Tsai D;Yan H;Butler PJ;Bazan GC;Phillip WA;Hickey RJ;Cremer PS;Vashisth H;Kumar M
通讯作者：
Kumar M
影响因子：
46.2
作者：
Hein JE;Fokin VV
通讯作者：
Fokin VV
影响因子：
56.9
作者：
Chowdhury, Maqsud R.;Steffes, James;McCutcheon, Jeffrey R.
通讯作者：
McCutcheon, Jeffrey R.