Ali Mohammad A, Volmert Brett, Evans Christopher M, Braun Paul V
Department of Materials Science and Engineering, Department of Chemistry, Beckman Institute for Advanced Science and Technology, and Materials Research Laboratory, University of Illinois Urbana Champaign, Urbana, Illinois 61801, USA.
Angew Chem Int Ed Engl. 2022 Oct 10;61(41):e202206061. doi: 10.1002/anie.202206061. Epub 2022 Sep 8.
Materials which selectively transport molecules offer powerful opportunities for concentrating and separating chemical agents. Here, utilizing static and dynamic chemical gradients, transport of molecules within swollen crosslinked polymers is demonstrated. Using an ≈200 μm static hydroxyl to hexyl gradient, the neutral ambipolar nerve agent surrogate diethyl (cyanomethyl)phosphonate (DECP) is directionally transported and concentrated 60-fold within 4 hours. To accelerate transport kinetics, a dynamic gradient (a "travelling wave") is utilized. Here, the non-polar dye pyrene was transported. The dynamic gradient is generated by an ion exchange process triggered by the localized introduction of an aqueous NaCl solution, which converts the gel from hydrophobic to hydrophilic. As the hydrophilic region expands, associated water enters the gel, and pyrene is pushed ahead of the expansion front. The dynamic gradient provides about 10-fold faster transport kinetics than the static gradient.
能够选择性转运分子的材料为浓缩和分离化学试剂提供了强大的机会。在此，利用静态和动态化学梯度，展示了分子在溶胀交联聚合物中的转运。使用约200μm的静态羟基到己基梯度，中性双极性神经毒剂替代物二乙基（氰甲基）膦酸酯（DECP）在4小时内定向转运并浓缩60倍。为了加速转移动力学，利用了动态梯度（“行波”）。在此，非极性染料芘被转运。动态梯度由局部引入NaCl水溶液触发的离子交换过程产生，该过程将凝胶从疏水性转变为亲水性。随着亲水性区域的扩展，相关的水进入凝胶，芘被推到扩展前沿之前。动态梯度提供的转移动力学比静态梯度快约10倍。
