Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation.
Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation.
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DOI：
10.1016/j.ancr.2016.04.001
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发表时间：
2016-06
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众所周知，表面悬浮的碳纳米管（CNT）样品可以通过离心来纯化以减少团聚体并增加单独分散的CNT。然而，离心并不总是制备用于生物医学应用的CNT样品的方案的一部分。在此，使用羧化的多壁碳纳米管（cMWCNT）悬浮在水中，没有表面活性剂，我们开发了一种Boehm滴定法离心cMWCNT悬浮液的分析，并使用它来显示，在水性cMWCNT悬浮液中的氧化的碳材料的表面酸性富集约40%，通过一个单一的低速离心步骤。未离心和离心的cMWCNT悬浮液之间的表面酸度的这种显著差异以前没有被认识到，并且是重要的，因为已知表面酸度的程度影响cMWCNT与生物系统的相互作用。
It is well known that surfactant-suspended carbon nanotube (CNT) samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs) suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ~40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.