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 CNTsDoes not damage the CNT walls during the procedure Reliable, rapid, and efficient techniqueEase of control during the filling processCan be scaled up
Market Application
BatteriesBiosensorsChemosensorsData storage unitsDrug delivery systems
Brochure
