Noriega-Navarro Roxana, Castro-Medina Jésica, Escárcega-Bobadilla Martha V, Zelada-Guillén Gustavo A
School of Chemistry, National Autonomous University of Mexico (UNAM), Circuito Escolar s/n, Ciudad Universitaria, Coyoacán, Mexico City 04510, Mexico.
Escuela Nacional Preparatoria 8 Miguel E. Schulz, Lomas de Plateros s/n, Álvaro Obregón, Mexico City 01600, Mexico.
Nanomaterials (Basel). 2020 Mar 27;10(4):614. doi: 10.3390/nano10040614.
Polymer-grafted nanomaterials based on carbon allotropes and their derivatives (graphene oxide (GO), etc.) are typically prepared by successive reaction stages that depend upon the initial functionalities in the nanostructure and the polymerization type needed for grafting. However, due to the multiple variables involved in the functionalization steps, it is commonly difficult to predict the properties in the final product and to correlate the material history with its final performance. In this work, we explored the steps needed to graft the carboxylic acid moieties in GO (COOH@GO) with a pH-sensitive polymer, poly[2-(diethylamino)ethyl methacrylate] (poly[DEAEMA]), varying the reactant ratios at each stage prior to polymerization. We studied the combinatorial relationship between these variables and the behavior of the novel grafted material GO--poly[DEAEMA], in terms of swelling ratio vs. pH (%Q) in solid specimens and potentiometric response vs. Log[H] in a solid-state sensor format. We first introduced -hydroxysuccinimide (NHS)-ester moieties at the -COOH groups (GO--NHS) by a classical activation with -ethyl-'-(3-dimethylaminopropyl)carbodiimide (EDC). Then, we substituted the NHS-ester groups by polymerizable amide-linked acrylic moieties using 2-aminoethyl methacrylate (AEMA) at different ratios to finally introduce the polymer chains via radical polymerization in an excess of DEAEMA monomer. We found correlated trends in swelling pH range, interval of maximum and minimum swelling values, response in potentiometry and potentiometric linear range vs. Log[H] and could establish their relationship with the combinatorial stoichiometries in synthetic stages.
基于碳同素异形体及其衍生物（如氧化石墨烯（GO）等）的聚合物接枝纳米材料通常通过连续的反应阶段制备，这些阶段取决于纳米结构中的初始官能团以及接枝所需的聚合类型。然而，由于官能化步骤涉及多个变量，通常很难预测最终产品的性能，也难以将材料的制备过程与其最终性能相关联。在这项工作中，我们探索了用pH敏感聚合物聚[甲基丙烯酸2-(二乙氨基)乙酯]（聚[DEAEMA]）接枝GO中的羧酸部分（COOH@GO）所需的步骤，在聚合前的每个阶段改变反应物比例。我们研究了这些变量与新型接枝材料GO-聚[DEAEMA]的行为之间的组合关系，包括固体样品中的溶胀率与pH值（%Q）以及固态传感器形式下的电位响应与Log[H]的关系。我们首先通过用1-乙基-3-(3-二甲基氨基丙基)碳二亚胺（EDC）进行经典活化，在-COOH基团处引入N-羟基琥珀酰亚胺（NHS）-酯部分（GO-NHS）。然后，我们使用不同比例的甲基丙烯酸2-氨基乙酯（AEMA）将NHS-酯基团替换为可聚合的酰胺连接丙烯酸部分，最后通过在过量的DEAEMA单体中进行自由基聚合引入聚合物链。我们发现了溶胀pH范围、最大和最小溶胀值区间、电位测定响应以及电位线性范围与Log[H]之间的相关趋势，并能够确定它们与合成阶段的组合化学计量之间的关系。
