(14ag) Polymer Based Hybrid Materials: From Molecular Design to Applications

Organic-inorganic nanocomposites with controlled hierarchical structures offer a particularly attractive platform for development of soft functional materials for various applications ranging from health care to energy storage. Here I am going to present how complexation of organic macromolecules and nanomaterials at molecular length scales and under mild conditions, as used by nature, can form advanced materials with exceptional engineering properties. Working with Prof. Matthew Tirrell and Prof. Juan de Pablo at the University of Chicago, I have synthesized patent-pending stable amorphous hybrid nanoparticles of controllable size and surface charge under mild conditions. These hybrid nanoparticles are composed of a polyelectrolyte, either polycation or polyanion and amorphous calcium phosphate nanospheres which are a few nanometer in size. The ACaP nanospheres are formed during synthesis and are uniformly dispersed inside the polymer matrix. We have also shown that through mixing these hybrid nanoparticles with their oppositely charged counterpart, it is possible to prepare injectable pastes with tunable rheological properties. The presence of stable ACaP nanospheres as an inexpensive, bioactive material along with very good handling properties makes these materials beneficial for tissue regeneration and dental applications. Moreover, I have been working on graphene based electrically conductive aerogels with exceptional thermal stability and compatibility with living cells.

In collaboration with prof. Mezzenga from ETH Zurich, we have been able to design gelatinâ??graphene conductive biopolymer nanocomposites with a record-low electrical percolation threshold of 3.3 Ã? 10^â??2 vol%, which arises from the homogeneous dispersion of the graphene nanosheets within the gelatin matrix. The results of this study have been published in Advanced Materials.

I also had the opportunity to get involved in a pioneering work on the understanding of glass-like dynamic properties of living cells. I joined Professor Fredbergâ??s lab at the Harvard University in 2012. As a member of a multidisciplinary team there, I was able to use my knowledge in physics of glass transition from my PhD work to study well-characterized endothelial and epithelial cell monolayer systems. We have shown that the mechanics of the cellular monolayer in the lung, and in other organ systems as well, may be dominated by glass transition and/or jamming as in polymeric and colloidal systems. Our findings which offer a unifying new lens into the biology of the cellular monolayers have been recently published in Nature Materials and Differentiation.

As a faculty member I would like to focus on understanding and fine-tuning the assembly of polymers and 2D nanomaterials into engineering systems and devices. Specifically, my main focus will be on developing compositionally and synthetically simplified organic-inorganic hybrid systems with lower production costs and competitive functionality in wide variety of applications including regenerative medicine and energy storage.

Teaching Interests:

I have several years of teaching experince of polymer courses including polymer physics, polymer chemistry and polymer characterization at both the undergraduate level and graduate level at the University of Tehran. I have also supervised more than 20 MSc and 2 PhD students in polymer science.

In addition to polymer courses, I would also welcome the opportunity to develop and teach classes related to colloidal science and hybrid materials.