Silver nanoparticles supported on carbon nanotube carpets: influence of surface functionalization
Silver nanoparticles supported on carbon nanotube carpets: influence of surface functionalization
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DOI：
10.1088/0957-4484/27/14/145603
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发表时间：
2016-04-08
期刊：
影响因子：
3.5
通讯作者：
Mukhopadhyay, Sharmila M.
中科院分区：
文献类型：
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作者：
Karumuri, Anil K.;Oswal, Dhawal P.;Mukhopadhyay, Sharmila M.
基于纳米颗粒的功能器件的有效性很大程度上依赖于载体的表面形态和面积。一种在不降低强度或增加体积的情况下增加可用表面积的新出现的有效方法是在表面附着合适的纳米管阵列，并在其上附着必要的纳米颗粒。该团队的早期出版物表明，地毯状的碳纳米管(CNT)阵列可以成功地生长在各种较大的碳衬底上，如石墨、泡沫和织物，这些衬底提供了适合于附着银纳米粒子(AgNPs)的分层多尺度支撑结构。纯碳纳米管阵列在流体应用中的一个限制因素是其疏水性，它可以减少水介质通过单个纳米管的渗流。以往的研究表明，用干(氧)等离子体处理碳纳米管地毯可以获得可逆的润湿性，而用湿(溶胶-凝胶)涂层处理可以获得永久性的润湿性。在本文中，我们报告了这些处理对AgNPs附着的影响，以及它们在水消毒处理中的效果。这两种亲水表面处理都显示碳纳米管地毯上的银负载量增加。氧等离子体处理的表面(O-CNT)显示出细小致密的AgNPs，而二氧化硅包裹的纳米管(SiO-CNT)显示出不均匀的AgNPs团簇。然而，在AgNP沉积过程中，O-CNT表面失去了亲水性，而SiO-CNT表面保持着亲水性。这一差异显著影响了这些材料的抗菌效果，正如在含有革兰氏阴性大肠杆菌(E.Coli，JM109)的模拟水中测试的那样。与等离子体处理的碳纳米管相比，二氧化硅包裹的碳纳米管基质上的AgNP对大肠杆菌的还原速率显著高于等离子体处理的碳纳米管基质上的AgNPs，尽管后者中的AgNP分布更细和更分散。这些结果为控制碳纳米管地毯润湿性的表面改性方法的不同方面及其在水处理应用中的适用性提供了重要的见解。
The effectiveness of nanoparticle-based functional devices depends strongly on the surface morphology and area of the support. An emerging powerful approach of increasing the available surface area without decreasing strength or increasing bulk is to attach arrays of suitable nanotubes on the surface, and to attach the necessary nanoparticles to them. Earlier publications by this team have shown that carpet-like arrays of carbon nanotubes (CNTs) can be successfully grown on a variety of larger carbon substrates such as graphite, foams and fabric, which offer hierarchical multiscale supporting architecture suitable for the attachment of silver nanoparticles (AgNPs). A limiting factor of pure CNT arrays in fluid-based applications is their hydrophobicity, which can reduce the percolation of an aqueous medium through individual nanotubes. Previous studies have demonstrated that the treatment of CNT carpets with dry (oxygen) plasma can induce reversible wettability, and treatment with wet (sol-gel) coating can impart permanent wettability. In this paper, we report the influence of such treatments on the attachment of AgNPs, and their effectiveness in water disinfection treatments. Both types of hydrophilic surface treatment show an increase in silver loading on the CNT carpets. Oxygen-plasma treated surfaces (O-CNT) show fine and densely packed AgNPs, whereas silica-coated nanotubes (silica-CNT) show uneven clusters of AgNPs. However, O-CNT surfaces lose their hydrophilicity during AgNP deposition, whereas silica-CNT surfaces remain hydrophilic. This difference significantly impacts the antibacterial effectiveness of these materials, as tested in simulated water containing Gram negative Escherichia coli (E. coli, JM109). AgNPs on silica-coated CNT substrates showed significantly higher reduction rates of E. coli compared to AgNPs on plasma-treated CNT substrates, despite the finer and better dispersed AgNP distribution in the latter. These results provide important insights into different aspects of surface modification approaches that can control the wettability of CNT carpets, and their applicability in water treatment applications.