Research Interest

Condensation polymerization – Control on PDI?

Due to a lack of control on the polydispersity, which is an inherent lacuna in the condensation polymerization technique, most of the research in polymer science is now on polymerizing vinyl-containing monomers. However, nature relies on the condensation polymerization methods and the macromolecules obtained so runs the entire cellular machinery. Aligning with nature brings in many aspects especially environmentally benign materials.

My main focus is on the development of techniques to generate various molecular architectures via condensation polymerization methods that are on par with free radical polymerization techniques. Polymers obtained through condensation routes incorporating esters, amides and ethers on the backbone are of biodegradable in nature and a development of techniques and catalysts towards condensation routes would directly address the environmental concerns without compromising the material requirement.

Condensation Polymerisation towards material applications: Poly(amines)

Nitrogen containing linear polyesters are an important class of polymers as they are easier to synthesize and provide opportunity for post-polymerization functionalization. This class of polymers can be prepared by transesterification polymerization and aza-Michael addition routes. Aza-Michael addition polymerization requires vinyl monomers (the source of such monomers largely depends on non-renewable resources) however the polymerization as such can be carried out at room temperature (30 °C), whereas monomers used for transesterification, can be bio-sourced, polymerization is carried out at comparatively high temperature and with constant removal of small molecule condensate. Nevertheless both the approaches leave a lesser environmental footprint and the final prepared polymer is biodegradable.

a) Development of catalysts to bring in the condensation polymerization to a lower temperature.

b) Adopting and designing synthetic strategies for preparing vinyl esters via eco-friendly methods for aza-Michael addition polymerization. 

c) Developing methods towards controlling polydispersity index, core-shell architecture of hyperbranched polymers

d) Quarternization of nitrogen on the backbone and subsequent anion exchange reactions

Condensation polymerization towards optoelectronic materials:

Chalcones are molecules prepared by Claisen-Smidth condensation by the reaction between aromatic aldehyde with aromatic methyl ketones in the presence of concentrated base such sodium hydroxide, or organo bases such as pyrolidine. The resulting in an a,b unsaturated ketone can be further functionalized to yield variety of push-pull systems, hole transporting systems, etc., by the design of moiety resulting after functionalization.

a) Selection and evaluation of catalysts to bring in the condensation polymerization to environmentally conducive conditions.

b) Adopting and designing synthetic strategies for preparing linear, hyperbranched and covalent organic framework.

c) Developing methods towards functionalization of backbone for modulating the backbone of the polymer towards better optoelectronic characteristics

Block copolymers

Cationic Ring Opening Polymerization (CROP) is a versatile polymerization technique which is adopted to prepare polymers of 2-alkyloxazolines. By choice of suitable pendants the block copolymers can be tailor made to be hydrophobic or hydrophilic. By balancing the HLB, the molecules can adopt various structures such as micelles, vesicles and various morphologies in solid state. If one of the block copolymer is chosen to have Lower Critical Solution Temperature (LCST), the morphologies that could be achieved can be tuned as the function of temperature.

a) The influencing parameter on the packing efficiency of pendant block copolymers.

b) Establishing the relationship between HLB, pendants and molecular weight