Name: Diptangshu Chakraborty
Diploma / M.Sc degree: Indian Institute of Technology, Kharagpur, India
(August 2006)

PhD Project: Diffusion and Exchange Studies of the Permeation Through Polymeric Capsule Molecules.

Abstract of Research Project

In the last two decades, scientists are very much interested in polyelectrolyte multilayers. They have also become successful to prepare multilayers of different polyelectrolytes on solid surfaces (especially on colloidal particles). After that the core colloidal particle is removed and as a result of it hollow capsules of polyelectrolytes are prepared. These hollow capsules of polyelectrolytes may be used as microreactors or microcarriers etc. To apply these hollow capsules as microreactors or microcarriers permeability is a key parameter which determines whether a probe molecule can enter into a capsule or not.

On the other hand, scientists have used the ‘Pulsed Field Gradient (PFG)’ NMR technique to measure the self-diffusion coefficient of molecules which contain NMR active nuclei. In heterogeneous systems, self-diffusion coefficient of a probe molecule changes with location; for example, in capsule dispersion the diffusion coefficient depends on whether a molecule is encapsulated or not. Therefore, applying PFG NMR it is possible to determine whether the probe molecule is inside or outside the capsule. Furthermore, the exchange rate of the probe moleculebetween the two sites can be measured also. Thus, with appropriate modeling we can also determine the permeability of the capsule wall.

So, in the present project we investigate the permeability of the hollow capsule wall by NMR spectroscopy and the factors (pH, salt concentration, temperature etc.) on which permeability depends. If we can determine the factors then we can control permeability by varying the external conditions.



Publications

D. Chakraborty, R. P. Choudhury, M. Schönhoff
Adsorption of aromatic alcohols into the walls of hollow polyelectrolyte capsules
Langmuir 26(15) (2010), 12940-12947.


Diptangshu Chakraborty
eMail: Diptangshu Chakraborty