Gazil Olivier, Gancheva Teodora, Bilodeau-Calame Michel, Favis Basil D, Virgilio Nick
CREPEC, Department of Chemical Engineering, Polytechnique Montréal C.P. 6079 Succursale Centre-Ville Montréal Québec H3C 3A7 Canada
Nanoscale Adv. 2020 Oct 5;2(11):5263-5270. doi: 10.1039/d0na00488j. eCollection 2020 Nov 11.
In this article, a dual-solvent method is presented which allows for precise control over the distribution of nanoparticles (NPs) in hydrogels. The technique is based on the interfacial reaction between a reducing agent (herein THPC) initially solubilized in the hydrogel phase, and an organometallic precursor (herein Au(PPh)Cl) solubilized in the surrounding organic liquid phase. When the organic phase is completely immiscible with water, the interfacial reaction yields a fragile monolayer film of NPs at the hydrogel surface. Then, the addition of a co-solvent (miscible with both aqueous and organic phases) allows precise tuning over the distribution of NPs, from a fine and well-anchored layer at the interface, to the whole gel volume. As a result, it is possible to independently control the size and concentration of NPs, and their distribution. The impact of such control is demonstrated with the reduction of -nitrophenol to -aminophenol catalyzed by gold nanoparticles (AuNPs). When AuNPs are mostly localized at the gel surface, the apparent reaction rate is more than 10× superior compared to AuNPs distributed in the whole gel - at comparable particle content and size. This approach is straightforward, decisive and compatible with broad arrays of NPs and hydrogel chemistries, and solvent combinations.
在本文中，我们提出了一种双溶剂法，该方法能够精确控制纳米颗粒（NPs）在水凝胶中的分布。该技术基于最初溶解在水凝胶相中的还原剂（此处为四羟甲基氯化磷（THPC））与溶解在周围有机液相中的有机金属前体（此处为三苯基膦氯化金（Au(PPh)Cl））之间的界面反应。当有机相与水完全不互溶时，界面反应在水凝胶表面产生一层脆弱的纳米颗粒单层膜。然后，添加一种共溶剂（可与水相和有机相混溶）可以精确调节纳米颗粒的分布，从界面处精细且牢固附着的层到整个凝胶体积。结果，可以独立控制纳米颗粒的尺寸、浓度及其分布。通过金纳米颗粒（AuNPs）催化对硝基苯酚还原为对氨基苯酚，证明了这种控制的影响。当金纳米颗粒大多位于凝胶表面时，与在整个凝胶中分布的金纳米颗粒相比，在可比的颗粒含量和尺寸下，表观反应速率高出10倍以上。这种方法简单直接、具有决定性，并且与广泛的纳米颗粒和水凝胶化学以及溶剂组合兼容。
