pH-Mediated Size-Selective Adsorption of Gold Nanoparticles on Diblock Copolymer Brushes
pH-Mediated Size-Selective Adsorption of Gold Nanoparticles on Diblock Copolymer Brushes
复制标题
pH 介导的金纳米粒子在二嵌段共聚物刷上的尺寸选择性吸附
DOI：
10.1021/acsnano.3c00212
复制
发表时间：
2023
期刊：
影响因子：
17.1
通讯作者：
Winey, Karen I.
中科院分区：
文献类型：
--
作者：
Kim, Ye Chan;Composto, Russell J.;Winey, Karen I.
通过设计与纳米颗粒具有可调相互作用的刺激响应表面，可以实现对界面处纳米颗粒的精确控制。在这项研究中，我们证明了聚合物刷可以选择性地吸附纳米颗粒的大小，通过调整缓冲溶液的pH值。具体而言，我们开发了一种简便的聚合物刷制备方法，使用对称的聚苯乙烯-b-聚（2-乙烯基吡啶）（PS-b-P2 VP）嵌段共聚物沉积在接枝聚苯乙烯层。该方法基于PS-b-P2 VP薄膜的组装，所述PS-b-P2 VP薄膜以在顶部PS-b-P2 VP层剥离后保留的平行层状取向。我们使用X射线反射率和原子力显微镜表征P2 VP刷。缓冲液的pH值用于定制柠檬酸盐包被的金纳米颗粒（AuNP）和顶部P2 VP块之间的相互作用，其表现类似于聚合物刷。在低pH值（pH = 4.0）下，P2 VP刷被强烈拉伸，并显示出高密度的吸引位点，而在中性pH值（pH = 6.5）下，P2 VP刷仅被轻微拉伸，并具有较少的吸引位点。具有耗散的石英晶体微天平监测作为AuNP直径（11和21 nm）和缓冲液的pH值的函数的吸附热力学。中性pH为纳米颗粒提供有限的渗透深度，并促进11 nm AuNP吸附的尺寸选择性。作为概念的证明，将P2 VP刷暴露于大和小AuNP的各种混合物以证明较小AuNP的选择性捕获。这项研究显示了使用pH敏感的聚合物刷创建用于纳米颗粒尺寸分离的设备的潜力。
Precise control of nanoparticles at interfaces can be achieved by designing stimuli-responsive surfaces that have tunable interactions with nanoparticles. In this study, we demonstrate that a polymer brush can selectively adsorb nanoparticles according to size by tuning the pH of the buffer solution. Specifically, we developed a facile polymer brush preparation method using a symmetric polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer deposited on a grafted polystyrene layer. This method is based on the assembly of a PS-b-P2VP thin film oriented with parallel lamellae that remains after exfoliation of the top PS-b-P2VP layer. We characterized the P2VP brush using X-ray reflectivity and atomic force microscopy. The buffer pH is used to tailor interactions between citrate-coated gold nanoparticles (AuNPs) and the top P2VP block that behaves like a polymer brush. At low pH (∼4.0) the P2VP brushes are strongly stretched and display a high density of attractive sites, whereas at neutral pH (∼6.5) the P2VP brushes are only slightly stretched and have fewer attractive sites. A quartz crystal microbalance with dissipation monitored the adsorption thermodynamics as a function of AuNP diameter (11 and 21 nm) and pH of the buffer. Neutral pH provides limited penetration depth for nanoparticles and promotes size selectivity for 11 nm AuNP adsorption. As a proof of concept, the P2VP brushes were exposed to various mixtures of large and small AuNPs to demonstrate selective capture of the smaller AuNPs. This study shows the potential of creating devices for nanoparticle size separations using pH-sensitive polymer brushes.