Tamoghna Bhattacharyya

Molecular discriminators using single wall carbon nanotubes

The interaction between single wall carbon nanotubes (SWNTs) and amphiphilic molecules has been studied in a solid phase. SWNTs are allowed to interact with different amphiphilic probes (e.g. lipids) in a narrow capillary interface. Contact between strong hydrophobic and amphiphilic interfaces leads to a molecular restructuring of the lipids at the interface. The geometry of the diffusion front and the rate and the extent of diffusion of the interface are dependent on the structure of the lipid at the interface. Lecithin having a linear tail showed greater mobility of the interface as compared to a branched tail lipid like dipalmitoyl phosphatidylcholine, indicating the hydrophobic interaction between single wall carbon nanotube core and the hydrophobic tail of the lipid. Solid phase interactions between SWNT and lipids can thus become a very simple but efficient means of discriminating amphiphilic molecules in general and lipids in particular.

Chirality sensitive binding of tryptophan enantiomers with pristine single wall carbon nanotubes

We report the differential binding nature of pristine single wall carbon nanotubes (SWNTs) with tryptophan enantiomers. The differential co-operative response between the pristine SWNTs (topologically chiral) and L- and D-tryptophan (geometrically chiral) provides the insight that geometrical chirality itself manifests with topological chirality in a complex way.

Induced chirality in single walled carbon nanotube based self-assembly

Chirality is an important determinant of the optical and electronic properties of single walled carbon nanotubes (SWNTs). Pristine zigzag SWNTs have been functionalized with lipids by a solid state functionalization process. Neither the lipids nor the SWNTs show a circular dichroism (CD) signal prior to functionalization. Upon functionalization, a change in the joint density of electronic states occurs which is reflected by a three-peak G′ band profile and the emergence of a CD signal. A molecular mechanism for the emergent CD signal associated with this lipid-specific self-assembly is described.

A Solid-State Chemistry Approach to Sense Polycyclic Aromatic Hydrocarbons From Environment Using Single-Wall Carbon Nanotubes

Solid-state functionalization of single-wall carbon nanotubes with hydrocarbons, including polycyclic aromatic hydrocarbons, is a potent viable approach for not only the characterization of new nano-structured materials but also the detection of polycyclic aromatic hydrocarbons at nanoscale. The proposed green functionalization process paves an insight that the molecular diffusion is directly linked with the availability of delocalized pi-electrons of hydrocarbons. The observation paves an important clue to design polycyclic aromatic hydrocarbon sensor at solid phase.