Polymer
& Materials Modelling
Overview
Mission
& Goals
Use modeling and computer
simulation to:
- Explore novel materials
- Establish fundamental insights
- Investigate structure-property relationships
- Derive surface properties of polymer coatings and adhesion
Competencies
- Molecular simulations (with full atomic description)
- Polymer modeling
- Statistical mechanics
- Quantum chemical calculations
- Bulk phase modeling
- Simulation of multi component systems
- Molecular theory
- Organic/inorganic materials modeling
Facilities
State-of-the-art workstations with graphics capabilities: 2 Silicon Graphics Octane (2 processors each), Silicon Graphics O2, Pentium Processor computers. Molecular modeling packages include Insight-II and Cerius for molecular/materials simulations, programs for ab-initio DFT, HF quantum mechanical calculations.
Glimpses
of current research
Single chain conformational analysis and statistical
properties
Statistically averaged dimensions of polymers as a function of their chemical structure. Our aim is to understand in detail the interplay between bond level behavior and overall statistically averaged polymer chain properties. This connection is provided by the Rotational Isomeric State (RIS) method and RIS Metropolis Monte Carlo (RMMC) method. Implementation of these methods for calculation of various conformationally averaged properties such as the chain dimensions, dipole moments, and optical anisotropy is our thrust objective. Various classes of polymers are currently being investigated.
Modeling of amorphous bulk state
Structure of amorphous polycarbonate from Monte Carlo, molecular mechanics and molecular dynamics simulations for estimation of structural properties and solubility parameter
Bulk properties of polymers such as solubility parameter, cohesive energy density, elastic properties are all dictated by the effect of chemical structure of polymer chain on intramolecular and intermolecular energy and structure. Our efforts are involved in developing a molecular level understanding of such behavior and material properties through fully atomistic simulations.
Optical properties of polymers
- Models for estimation of optical anisotropy and linear optical properties of organic molecules, monomers, polymer chains and segments in condensed phase.
- Birefringence calculation using atomistic modeling, with full chemical structure description of polymer chains
Polymer surfaces and thin films
- Structural and thermodynamic properties as dictated by chemical structure of polymer.
Molecular thermodynamics
- Estimation of thermodynamic interactions in homopolymers, copolymers and blends through models for polymer surfaces and blends. Properties of interest include surface energy and tension, and interfacial energy between dissimilar polymers.
Thermal and mechanical properties
- Development of new QSPR Models for estimation of glass transition temperature, solubility parameter, coefficient of thermal expansion, tensile strength and impact strength of polymers. The ability to predict thermal and mechanical properties of polymers by easily executable models has prime importance in the industry. Descriptors that can capture the wide range of physical effects that govern polymer properties in the condensed phase are not generally available. Our aim is two-fold: (i) use available QSPR models to predict properties of polymers when applicable, (ii) develop new QSPR models that incorporate descriptors not currently available in the area of polymer science.
Rheo-optics and melts
- Simulations of stress-optical coefficients in the glassy and melt states
- Solution and melt viscosity prediction as affected by polymer structure development.
Nano materials and composites
- Molecular modeling of intercalated and exfoliated polymer-clay systems. Development of new statistical mechanical models for such hybrid systems. Polymers in 1 and 2 dimensional confinement behave very differently structurally and dynamically from their bulk phase counterparts. Behavior of polymers in confinement dictates the properties of polymers in a variety of commercial applications as well as in a variety of multiphase systems. We are pursuing investigations of polymers under specific confinements using molecular simulations (Monte-Carlo, Molecular Mechanics and Molecular Dynamics) in conjunction with spectroscopic techniques.
Ab-initio/ DFT modeling of organic molecules
- Quantum mechanical calculations for the electronic structure and conformational features of small organic molecules are important to establish parameters for force-fields and atomistic modeling. In cases where standard and general purpose force-fields are unable to correctly reproduce spectroscopic data, optical properties, and conformational minima, such calculations provide suitable information for the simulations of chain molecules that are composed of organic fragments. Our current efforts include ab-initio calculations for deriving the conformational and optical properties of small molecules and new force-field development.
Exploratory materials science & technology
- Advanced polymer membranes structures: Full atomic detailed structures of amorphous polymers for gas barrier and solute separation membrane applications.
- Zeolite-Organic & Zeolite-Polymer hybrids: Structures and dynamics of organic molecules and polymers within zeolite framework channels.
Contact
Dr. Upendra Natarajan
National Chemical Laboratory ,
Pune 411 008
Email :upendra@poly.ncl.res.in
Phone :+91-20-2589 3300 (extn 2154)
Fax :+91-20-2589 3234