Functional Organic Polymers and Nanostructures
Gavvalapalli Research Group
To push the frontiers of organic electronics, energy harvesting and storage systems, and extend their life time there is a need to develop smart materials that are programmable to self-assemble into desired structures, mechanically compliant, and self-healable.
Our research program focuses on the rational design and development of structurally precise organic polymeric materials and nanostructures. Our group’s core strength is design, development, synthesis, and structural characterization of functional polymers and self-assembly of organic molecules and nanostructures. Students in my research group are trained at the interfaces of organic chemistry, polymer chemistry and nanoscience, and gain expertise in the design and synthesis of small molecules, polymers and nano/colloidal particles. In addition to the synthesis of materials, students routinely perform electron microscopy, X-ray diffraction, and electrochemical and optical characterization, alongside basic material characterization.
Elastic and Self-healable Polymers for Organic Electronics
This project aims to understand the interplay of electronic and mechanical properties in π-conjugated polymers to develop mechanically compliant elastic and self-healable electronic materials. The developed materials are highly desirable in various traditional (eg. solar cells, transistors) as well as non-traditional (eg. electronic skin, artificial retina) electronic applications.
Taking cues from the easy processability of reversible and thixotropic non-π-conjugated polymer gels, we report herein for the first time a simple strategy to obtain reversible and thixotropic π-conjugated polymer ionic network (π-PIN) gels. Reversible and thixotropic π-PIN gels are generated by synergistically combining the intriguing properties of π-conjugated polymers with the dynamic properties of ionically cross-linked networks.
Publication: Macromolecules, 2017, 50, pp 7577–7583. DOI: 10.1021/acs.macromol.7b01896
Shape Controlled Synthesis of Organic π-conjugated Nanoparticles
This project aims to develop a rational synthetic approach to control the shape of organic π-conjugated particles. The design rules for shape controlled synthesis of organic nanoparticles is relatively less understood compared to metal nanoparticles. Polyhedral particles of different shape are useful to control the assembly and charge/energy transport at mesosocale, and also open the door for novel photonic materials.
Previous work had relied on the use of aliphatic amphiphiles which lack structural diversity and thus do not provide a range of amphiphile-particle facet interaction energies and result in a limited range of particle shapes. Our work is focused on the design, synthesis and use of novel aryl amphiphiles as shape-directors. By modulating the aryl hydrophobe structure, the interaction energies of the amphiphile-particle facets are varied, thus changing the relative growth rate of the different facets and resulting in a range of different particle shapes.
Publication: Chem. Commun., 2019, 55, 1306-1309. DOI: 10.1039/C8CC09405E
Developing Novel Building Blocks for Disruptive Design of 1D- and 2D-π-Conjugated Polymers
This project aims to develop novel building blocks that render a new class of 1D-π-conjugated polymers as well as rational and controlled synthesis of 2D-π-conjugated polymers. Although appending pendant solubilizing chains is a successful strategy to gain control over the synthesis and properties of conformationally flexible 1D-π-CoPs, it is not effective for the 2D-π-conjugated materials of larger width due to strong van der Waals interactions.
Inspired from the polypeptide β-strand architecture, we have designed and developed novel bifacial π-conjugated polymers that are soluble despite the absence of pendant solubilizing chains. By proper design i.e., by incorporating functional moieties that undergo lateral polymerization, the high molecular weight, soluble bifacial polymers can be converted into ladder polymers and nanoribbons. Finally, similar to the β-strands in β-fibrils, the bifacial architecture provides control over face-to-face interactions in 2D-π-CoPs, which enables control of the growth, assembly and solution processability of the 2D-π-CoPs.
Publication: Chem. Sci., 2019, Advance Article. DOI: 10.1039/C9SC01724K