Our research aims to advance our theoretical understanding of both natural and synthetic soft condensed matter systems. We leverage the tools of statistical mechanics, continuum mechanics and computer simulation to bridge microscopic details with the emergent properties and phenomena displayed by these systems. Our current interests are diverse – ranging from the nonequilibrium phase behavior and dynamics of active colloids and driven polymers to understanding the self-assembly pathways of complex phases. The unifying theme in these seemingly disparate areas is the significance of both conservative and nonconservative (e.g., hydrodynamic, active) forces in shaping the underlying dynamic landscape and material properties. We endeavor to investigate this interplay of thermodynamic and dissipative forces by utilizing and devising simulation and analytical techniques at the coarse-grained length and time scales of interest. Moreover, we aim to study systems that have clear connections to experiments and venture to make meaningful and experimentally verifiable predictions.
We are a diverse group of scientists that value, respect and welcome people regardless of race, ethnicity, religion, culture, gender identity, sexuality, age and disability.
Graduate Student (MSE)
B.S. MSE, Penn State
yoshi_chiu@berkeley.edu
Graduate Student (MSE)
B.S. MSE, Michigan
danevans@berkeley.edu
Graduate Student (AS&T)
B.S. Physics, Peking University
jiechao_feng@berkeley.edu
Postdoctoral Scholar
Ph.D., Cambridge University
daking2@lbl.gov
Graduate Student (MSE)
B.S. MSE, UC Berkeley
langford.luke@berkeley.edu
Graduate Student (MSE)
Co-advised w/ Phil Messersmith
B.S. Chemistry, U. Chicago
nivedina@berkeley.edu
Graduate Student (MSE)
B.S. CS and Math, Harvey Mudd
eric_weiner@berkeley.edu
Theory of Nonequilibrium Multicomponent Coexistence.
Y.J. Chiu*, D. Evans*, A. K. Omar
arXiv:2409.07620
Phase Separation, Capillarity, and Odd Surface Flows in Chiral Active Matter.
L. Langford and A. K. Omar
arXiv:2408.14686 (In Review)
Theory for the Anomalous Phase Behavior of Inertial Active Matter.
J. Feng and A. K. Omar
arXiv:2407.08676 (In Review)
The Mechanics of Nucleation and Growth and the Surface Tensions of Active Matter.
L. Langford and A. K. Omar
arXiv:2407.06462 (In Review)
The Flux Hypothesis for Odd Transport Phenomena.
C. Hargus, A. Deshpande, A. K. Omar, K. K. Mandadapu
arXiv:2405.08798 (In Review)
Theory of Nonequilibrium Coexistence with Coupled Conserved and Nonconserved Order Parameters.
D. Evans and A. K. Omar
arXiv:2309.10341 (In Review)
Theory of Capillary Tension and Interfacial Dynamics of Motility-Induced Phases.
L. Langford and A. K. Omar
Phys. Rev. E 2024 110, 054604
[Editors’ Suggestion]
Oversaturating Liquid Interfaces with Nanoparticle-Surfactants.
X. Wu, H. Xue, Z. Fink, B. A. Helms, P. Ashby, A. K. Omar, T. P. Russell
Angew. Chem. Int. Ed. 2024, 63, e202403790
Self-Propulsion by Directed Explosive Emulsification.
X. Wu, H. Xue, G. Bordia, Z. Fink, P. Y. Kim, R. Streubel, J. Han, B. A. Helms, P. Ashby, A. K. Omar, T. P. Russell
Adv. Mater. 2024, 2310425
Phase Coexistence Implications of Violating Newton’s Third Law.
Y.-J. Chiu and A. K. Omar
J. Chem. Phys. 2023, 158, 164903
Mechanical Theory of Nonequilibrium Coexistence and Motility-Induced Phase Separation.
A. K. Omar*, H. Row*, S. A. Mallory*, J. F. Brady
Proc. Natl. Acad. Sci. U. S. A. 2023, 18, e2219900120
Remembering the Work of Phillip L. Geissler: A Coda to His Scientific Trajectory.
Annu. Rev. Phys. Chem. 2023, 74, 1
Ballistic Ejection of Microdroplets from Overpacked Interfacial Assemblies.
X. Wu, G. Bordia, R. Streubel, J. Hasnain, C. C. S. Pedroso, B. E. Cohen, B. Rad, P. Ashby, A. K. Omar, P. L. Geissler, D. Wang, H. Xue, J. Wang, T. P. Russell
Adv. Funct. Mater. 2023, 2213844
Tuning Nonequilibrium Phase Transitions with Inertia.
A. K. Omar, K. Klymko, T. GrandPre, P. L. Geissler, J. F. Brady
J. Chem. Phys. 2023, 158, 074904
Topological Forces in a Model System for Reptation Dynamics.
A. K. Omar, Y. Lu, L. An, Z.-G. Wang
arXiv:2207.05351
Boundary Design Regulates the Diffusion of Active Matter in Heterogeneous Environments.
K. J. Modica, A. K. Omar, S. C. Takatori
Soft Matter 2023, 19, 1890
The Influence of Molecular Design on Structure-property Relationships of a Supramolecular Prodrug.
K. G. DeFrates*, J. Engström*, N. A. Sarma, A. Umar, J. Shin, J. Cheng, W. Xie, D. Pochan, A. K. Omar, P. Messersmith
Proc. Natl. Acad. Sci. U. S. A. 2022, 44, e2208593119
Dynamic Concentration Scales of Active Colloids.
S. A. Mallory, A. K. Omar, J. F. Brady
Phys. Rev. E 2021, 104, 044612
Phase Diagram of Active Brownian Spheres: Crystallization and the Metastability of Motility-induced Phase Separation.
A. K. Omar, K. Klymko, T. GrandPre, P. L. Geissler
Phys. Rev. Lett. 2021, 126, 188002
[Cover Article; Editors’ Suggestion; and Featured in Physics Magazine]
Microscopic Origins of the Swim Pressure and the Anomalous Surface Tension of Active Matter.
A. K. Omar, Z.-G. Wang, J. F. Brady
Phys. Rev. E 2020, 101, 012604
Swimming to Stability: Structural and Dynamical Control via Active Doping.
A. K. Omar, Y. Wu, Z.-G. Wang, J. F. Brady
ACS Nano 2019, 13, 560
Mechanisms of Diffusion in Associative Polymer Networks: Evidence for Chain Hopping.
P. B. Rapp*, A. K. Omar*, B. Silverman, Z.-G. Wang, D. A. Tirrell
J. Am. Chem. Soc. 2018, 140, 14185
Shear-Induced Heterogeneity in Associating Polymer Gels: Role of Network Structure and Dilatancy.
A. K. Omar and Z.-G. Wang
Phys. Rev. Lett. 2017, 119, 117801
Analysis and Control of Chain Mobility in Protein Hydrogels.
P. B. Rapp, A. K. Omar, J. J. Shen, M. E. Buck, Z.-G. Wang, D. A. Tirrell
J. Am. Chem. Soc. 2017, 139, 3796
Aggregation Behavior of Rod-Coil-Rod Triblock Copolymers in a Coil-Selective Solvent.
A. K. Omar, B. Hanson, R. T. Haws, Z. Hu, D. A. Vanden Bout, P. J. Rossky, V. Ganesan
J. Phys. Chem. B 2015, 119, 330
Complexation between Weakly Basic Dendrimers and Linear Polyelectrolytes: Effects of Grafts, Chain Length, and pOH.
T. Lewis, G. Pandav, A. Omar, V. Ganesan
Soft Matter 2013, 9, 6955
MSE 159: Introduction to Soft Matter Soft matter is ubiquitous in synthetic materials and plays a central role in living systems. This course aims to provide students with an introduction to the physics that govern the structure and dynamics of soft mater systems, including polymers, colloids, surfactants, membranes, and active matter. A particular emphasis will be placed on connecting a microscopic physical picture to the emergent phenomena and properties of interest using scaling theory and statistical mechanics. Specific topics will include Brownian motion and colloidal dynamics, the depletion force, polymer chain conformation, rubber elasticity; and surfactant and liquid crystal thermodynamics.
MSE 201B: Thermodynamics, Phase Behavior and Transport Phenomena in Materials This course covers the laws of classical thermodynamics, principles of statistical mechanics, and laws governing the transport of mass and momentum in materials. Applications include the construction of equilibrium and nonequilibrium phase diagrams and the kinetics of phase transformations in both soft and hard materials.
Our student/postdoc office is located at 248 Hearst Memorial Mining Building (HMMB). Ahmad’s office is located at 225 HMMB. Stop by and visit us!