Membrane Synthesis
Ultrafiltration (UF) and nanofiltration (NF) membranes are used for water treatment, protein purification, viral filtration, etc. Instead of non-solvent induced phase separation (NIPS), we utilize self-assembly as a route for producing mesoporous polymeric materials that can be used as UF and NF membranes. Additionally, the conventional membranes have a fixed pore size, and thus a limited selectivity. We produce membranes that have better separation performance compared to conventional membranes and are also responsive to temperature and pH.
PFAS removal from water resources
Per- and polyfluoroalkyl substances (PFAS) are a large family of chemicals that can be characterized by a high level of chemical and thermal stability. Additionally, many PFAS express surfactancy which, in conjunction with their stability, has led to widespread contamination of water supplies across the globe. The resulting contamination is harmful to many organisms, including humans, which has in turn warranted interest in remediation methods that are effective and do not produce harmful secondary waste. Foam fractionation is a promising technological solution, which has exhibited the capability of removing above 95% of PFAS from landfill leachate as well as ground water contaminated with aqueous film-forming foam (AFFF). We are developing mass transport modeling equations in order to design high efficiency foam fractionation systems in addition to characterizing aqueous PFAS systems via spectroscopy (light scattering, X-ray scattering, and nuclear magnetic resonance) and interfacial property measurements.
Nanoemulsions
Nanoemulsions have attractive features including long-term stability without going through coalescence, tunable flow behavior (from liquid to solid) and optical properties (from opaque to nearly transparent). One of the applications of nanoemulsions is to use them as templates for making mesoporous polymers. Nanoemulsion size, stability, and droplet-droplet interactions strongly depend on the nature of the surfactant used as a stabilizer. The long-term goal of this project is to construct a phase diagram to understand the different states of nanoemulsions for their potential use as templates: 1- colloidal gas, 2- colloidal liquid, 3- gel, 4- attractive glass, 5- repulsive glass, and 6) compressed droplets. The other important aspect of nanoemulsion is studying its rheology, where we use a combination of theoretical and machine learning approaches to model the flow behavior of this class of colloidal systems based on their controllable structural variables.
Biopolymer Porous Polymers: Towards Bio compatibility and Biodegradability
We synthesize multifunctional porous polymers through (nano)emulsion- and foam-templating methods. The obtained porous polymers are used for different applications, such as water retention in soil for agriculture, microfiltration membranes, and adsorbents for heavy metal removal.
Rheology of Structured Fluids
We measure rheological material functions (e.g., yield stress, relaxation time, viscoelastic moduli) for suspensions, (nano)emulsions, liquid crystals, etc. in different states (liquid, glass and gel). For example, surfactants and block copolymers self-assemble in different liquid crystalline structure in water/oil mixtures (lyotropic liquid crystals). We study the rheological fingerprints of these structured fluids through rheology and scattering methods.
Hydrogels
Hydrogels are crosslinked polymeric networks that swell in water, and they have use in a variety of applications such as tissue engineering, contact lenses, prostheses, drug delivery, and agriculture. We study the molecular network and rheology of hydrogels. We also implement porosity and stimuli-responsiveness in hydrogels.
Phase Separation in Soft Matter
Phase separation in complex fluids such as polymers, surfactants, colloids, and biological materials plays a prominent role in determining morphology as well as mechanical, electrical, and transport properties due to pattern evolution in multicomponent mixtures of materials. We study phase separation in materials with potential applications in water purification membranes, batteries, and plastic recycling.
Dynamic phase diagram of PS/PVME blends, showing the types of phase separation occurring at each region: (A) normal NG, (B) SD, (C) transient gel induced VPS, (D) coalescence induced VPS, (E) aggregating NG, and (F) normal NG. Typical morphologies with phase separation time are shown next to the phase diagram. Mw,PS = 248 Kg/mol, Mn,PS = 87 Kg/mol, Tg,PS = 94 °C, Mw,PVME = 110 Kg/mol, Mn,PVME= 64 Kg/mol, Tg,PVME = -32 °C.