Characterization techniques carbon nanotube functionalization

In Chapter 9, the online size characterization of nanofibers and nanotubes is discussed by C. 1. Unrau, R. L. Axelbaum, P. Biswas and P. Fraundorf. First, a review of this subject is introduced and a method for online size characterization of carbon nanotubes developed by the authors is presented. This method employs a differential mobility analyzer, which classifies particles by their electrical mobility. It is concluded that (i) the presented method of online size characterization allows for faster optimization of gas-phase carbon nanotube production (ii) it could be valuable for online air quality measurements related to nanofibers and nanotubes and (iii) by identifying functional relationships between length and width, microscopy can make it possible for the online techniques described here to infer the size distribution of both. 

In Chapter 4, we discussed an important 2-D nanoarchitecture - thin films. As long as the thickness is <100 nm, these are properly classified within the nanomaterials umbrella. Though spin-coating may be able to afford thin films of this overall thickness, these types of coatings are generally deposited using vapor deposition techniques (PVD, CVD, and ALD). The current buzz related to 2-D nanomaterials is related to the synthesis, characterization, and functionalization of the theoretical sub-unit of carbon nanotubes - graphene sheets. 

Many years have passed since the early days of AFM, when adhesion was seen as a hindrance, and it is now regarded as a useful parameter for identification of material as well as a key to understanding many important processes in biological function. In this area, the ability of AFM to map spatial variations of adhesion has not yet been fully exploited but in future could prove to be particularly useful. At present, the chemical nature and interaction area of the AFM probe are still rarely characterized to a desirable level. This may be improved dramatically by the use of nanotubes, carbon or otherwise, with functionalized end groups. However, reliance on other measurement techniques, such as transmission electron microscopy and field ion microscopy, will probably be essential in order to fully evaluate the tip-sample systems under investigation. 

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