Abstract
Carbon nanotubes (CNTs) are formed by rolling up an individual or several graphitic layers in a concentric manner. CNTs have unique electronic, mechanical, and thermal properties which make them attractive for several physical applications. In addition to these properties, their unique hollow tubular structure allows the storage of foreign materials in the CNT core, creating a novel class of hybrid nanomaterials. The insertion of guest materials in the hollow nanochannels of CNTs results in the CNTs having new properties such as unusual electrical, magnetic, electromagnetic, electrochemical, and optical properties.
There are two approaches to fill CNTs, ex-situ filling, and in-situ filling. Ex-situ filling is a multi-step process consisting of synthesizing the CNTs, opening the closed caps of the CNTs, and filling the open CNTs. This method has several limitations. The opening of the nanotubes is a destructive process and its efficiency is dependent on the degree of dispersion of the CNTs. In addition, the fillers are often segments or particles, resulting in non-complete (or non-uniform) filling of the carbon nanotubes, and the fillers inside the open CNTs are not protected at the end. On the other hand, the in-situ filling method is a single-step process that generates the CNTs with ends closed at both sides, keeping the capsule intact and the core material preserved from undesired chemical reactions with the surrounding environment. Even though in-situ methods have been used to successfully encapsulate inorganic and organic material inside CNTs, they still suffer from several drawbacks such as lower efficiency, infeasibility to fill carbon nanotubes by multi-component fillers such as metal alloys, and poor control over the filling process.
FIU scientists have developed methods to fill metal sulfides such as nickel sulfide, iron sulfide, and cobalt sulfide inside CNTs. The process uses an in situ chemical vapor deposition technique. The CNTs growth and filling of metal sulfide happen simultaneously, and the CNTs can be completely and uniformly filled with metal sulfide filler up to several micrometers in length. This method has been proven to be a rapid, reliable, and efficient process, and enables the large amount production of metal sulfide filled CNTs.
Benefit
- Complete and continuous filling of the CNTs
- Does not damage the CNT walls during the procedure
- Reliable, rapid, and efficient technique
- Ease of control during the filling process
- Can be scaled up
Market Application
- Batteries
- Biosensors
- Chemosensors
- Data storage units
- Drug delivery systems
Brochure
