Srivastava Lab


Electrostatic Self-ASsembly of Soft Materials

Research in the Srivastava Lab utilizes the self-assembly of mesoscopic building blocks to engineer soft materials with real-life applications. Our focus is on polyelectrolyte complexation – the associative phase separation of oppositely charged polyelectrolytes, and our aim is to address the fundamental question: “How can we leverage macromolecular design to modulate the length scale of phase separation in complex coacervates?"

Self-Assembled Polyelectrolyte Complex Networks and Hydrogels

Scaffoldings for Wet Adhesives and 3D Bioprinting Inks 

We develop electrostatically self-assembled networks that are used as scaffolds addressing challenges in the mechanical properties of a wide range of conventional covalent-type hydrogels. This approach enables the development of interpenetrating polymer networks comprising covalent and electrostatic self-assembled networks. Our characterization of the structure and material properties demonstrated synergetic improvements in shear and tensile strengths of hydrogels while preserving the microstructure of electrostatically self-assembled networks. This proved instrumental in the delivery, injection, and 3D printing of biopolymer inks and bioadhesives in biomedically-relevant environments.

Selected Relevant Publications:

Advances, Applications, and Emerging Opportunities for Electrostatic Hydrogels, H. Senebandith,# D. Li,# S. Srivastava*, In review (2023).

Block Polyelectrolyte Additives Modulate the Viscoelasticity and Enable 3D Printing of Gelatin Inks at Physiological Temperatures, T. Göckler,^# D. Li,^# F. Albreiki,^# A. Grimm, F. Mecklenburg, U. Schepers,* S. Srivastava*, In review (2023). ChemRxiv

Polyelectrolyte Complex Hydrogel Scaffoldings Enable Extrusion-based 3D Bioprinting of Low-Viscosity Bioinks, T. Göckler,# D. Li,# A. Grimm, F. Mecklenburg, M. Grün, U. Schepers,* S. Srivastava*, In review (2023). ChemRxiv

Polyelectrolyte Complex Scaffoldings for Photocrosslinked Hydrogels, D. Li,# M. Ghovvati, N. Annabi, S. Srivastava*, Molecular Systems Design & Engineering 8, 611-623 (2023). [PDF]

Polyelectrolyte Complex-Covalent Interpenetrating Polymer Network Hydrogels, D. Li,# T. Göckler,# U. Schepers, S. Srivastava*, Macromolecules 55, 4481 (2022). [PDF]

Structure, Morphology, and Rheology of Polyelectrolyte Complex Hydrogels Formed by Self-Assembly of Oppositely Charged Triblock Polyelectrolytes, S. Srivastava,* A. E. Levi, D. J. Goldfeld, and M. V. Tirrell*, Macromolecules, 53, 5763 (2020). [PDF]

Gel Phase Formation in Dilute Triblock Copolyelectrolyte Complexes, S. Srivastava, M. Andreev, A. E. Levi, D. J. Goldfeld, J. Mao, W. T. Heller, V. Prabhu, J. J. de Pablo, and M. V. Tirrell, Nature Communications 8, 14131 (2017). [PDF]

Stabilizers for Water-Air and Water-Water Interfaces

We explore fundamental questions related to the interfacial assembly of surfactants and (macro)molecules at water-air and water-water interfaces. We developed a new paradigm for membraneless stabilization of complex coacervates microdroplets, resulting in a new class of materials known as complex coacervate emulsions that rely solely on the assembly of comb polyelectrolytes at the coacervate-water interface. Our approaches have expanded the utility of complex coacervates as protein encapsulants and colloidal bioreactors.

Selected Relevant Publications:

Comb Polyelectrolytes Stabilize Complex Coacervate Microdroplet Dispersions, S. Gao,# S. Srivastava*, ACS Macro Letters 11, 902 (2022). [PDF]

Salt Weakens Intermicellar Interactions and Structuring in Bulk Solutions and Foam Films, C. Ochoa, S. Gao,# S. Srivastava,* and V. Sharma*, Langmuir 38, 11003 (2022). [PDF]

Foam film stratification studies probe intermicellar interactions, C. Ochoa, S. Gao,# S. Srivastava,* and V. Sharma*, Proceedings of the National Academy of Sciences, 118, e2024805118 (2021). [PDF]

Protein–Polyelectrolyte Complexes and Micellar Assemblies, S. Gao,^ A. Hokar,^ and S. Srivastava*, Polymers, 11, 1097 (2019). [PDF]

Interfacial Stabilization of Aqueous Two-Phase Systems: A Review, C. Fick,# Z. Khan,# S. Srivastava*, In review (2023).

A User-friendly Graphical User Interface for Dynamic Light Scattering Data Analysis, M. Salazar,## H. Srivastav,## A. Srivastav, S. Srivastava*, In review (2023). ChemRxiv

Fundamentals of Complex Coacervates

Our group explores fundamental questions on the properties of polyelectrolyte complexes. We developed a new framework termed time-ionic strength superposition, to link the influence of salt and polyelectrolyte counterions on the flow behavior of polyelectrolyte complex coacervates. Our framework enables a facile approach to probe long-time relaxation dynamics of polyelectrolyte chains in complex coacervates. We also study the non-trivial properties and phase behavior of complex coacervates by probing the ion valency and chain lengths to determine the polymer content and rheological properties that are significant in industrial applications.

Selected Recent Publications:

Influence of Divalent Ions on Composition and Viscoelasticity of Polyelectrolyte Complexes, D. Iyer,# V. M. S. Syed,# S. Srivastava*, Journal of Polymer Science, 59, 2895 (2021). [PDF]

Effect of Solvent Quality on the Phase Behavior of Polyelectrolyte Complexes, L. Li, A. M. Rumyantsev, S. Srivastava,* S. Meng, J. J. de Pablo* and M. V. Tirrell*, Macromolecules, 54, 105 (2021). [PDF]

Time−Ionic Strength Superposition: A Unified Description of Chain Relaxation Dynamics in Polyelectrolyte Complexes, Vaqar M. S. Syed, Samanvaya Srivastava*, ACS Macro Letters, 9, 1067 (2020). [PDF]

Macromolecules, 53, 7835 (2020) [PDF]; Macromolecules 51, 2988 (2018) [PDF]; Soft Matter 14, 2454 (2018) [PDF]; Advances in Chemical Physics 161, 499 (2016) [PDF].

Sustainable Plastics and Composites

Low-Energy and Low-Carbon-Intensity Inorganic-Organic Composites and Cements

We pursue low-energy cost, environmentally friendly approaches to produce composites that rival commercial construction materials by utilizing products obtained from the chemical recycling of plastics. To do this, we integrate naturally occuring zeolite minerals with organic molecules sources from post-consumer-use polyurethane foams (mattresses and cushions) to create organic-inorganic composites with tensile and compressive strengths exceeding cement.

Selected Relevant Publications:

High-strength Organic-Inorganic Composites for Soundproofing and Thermal Insulation, M. Galadari,^# D. Iyer,^# V. Huaco,## F. Wirawan,## R. Martinez, M. T. Gallagher, L. Pilon, K. Ono, D. Simonetti, G. Sant, S. Srivastava*, In review (2023).

Electrosterically Controlling Aggregation and Yielding Characteristics of Portlandite Suspensions, S. B. Kandy,* N. Neithalath, M. Bauchy, E. Garboczi, T. Gaedt, S. Srivastava, G. Sant*, Langmuir. In Print (2023).

Metal Cations as Inorganic Structure-Directing Agents during the Synthesis of Phillipsite and Tobermorite, J. C. Vega-Vila, A. Holkar,# R. Arnold, D. Prentice, S. Dong. L. Tang, E. La Plante, K. Ellison, A. Kumar, M. Bauchy, S. Srivastava,* G. Sant, D. Simonetti*, Reaction Chemistry & Engineering 8, 1176-1184 (2023). [PDF]

Hybrid Organic–Inorganic Composites Based on Glycolyzed Polyurethane, D. Iyer,# M.T. Gallagher, D.A. Simonetti, G.N. Sant, S. Srivastava*, ACS Sustainable Chem. Eng. 10, 17116−17123 (2022). [PDF]

Ultrafast Stiffening of Concentrated Thermoresponsive Polymer-mineral Suspensions, S. B. Kandy, I. Mehdipour, N. Neithalath, A. Kumar, M. Bauchy, E. Garboczi, S. Srivastava, T. Gaedt, G. Sant, Materials & Design 221, 110905 (2022). [PDF]

Temperature-induced aggregation in portlandite suspensions, S. B. Kandy, I. Mehdipour, N. Neithalath, M. Bauchy, E. J. Garboczi, S. Srivastava, T. Gaedt, and G. N. Sant, Langmuir, 36, 10811 (2020).  [PDF]

Dispersing Nano- and Micro-sized Portlandite Particulates via Electrosteric Exclusion at Short Screening Lengths, J. Timmons,^ I. Mehdipour,^ S. Gao, H. Atahan, N. Neithalath, M. Bauchy, E. Garboczi, S. Srivastava*, and G. Sant*, Soft Matter, 16, 3425 (2020). [PDF]