Grason Research Group

Greg Grason
Greg Grason

Professor

Our research explores the role of geometric frustration in soft matter and polymeric assemblies through the combined lens of condensed matter theory, statistical physics and differential geometry. In assemblies, frustration arises from interactions between molecular or particulate “building blocks” that favor geometrically incompatible patterns of order. Counterintuitively, frustration often leads to self-organized states that are more exquisitely structured, and more robustly controlled, than their canonical, unfrustrated counterparts.
View Profile

Current research

Snapshot of a self-assembly of cuboidal subunits into a hyperbolic tubule.

Geometrically frustrated soft matter

Geometrically frustrated assembly is an emerging paradigm in which the local misfits between soft “building blocks" give rise to stress gradients within a self-assembling structure on size scales that far exceed the block dimensions. The accumulation of long-range stresses in frustrated assemblies underlies scale-dependent behaviors without counterpart in canonical assemblies, such as equilibrium self-limitation.  Our research uses theory and computational models to study the basic physical principles of frustrated self-assembly based on generic minimal models, while at the same time exploring how effects of frustration propagate up from particle-scale properties to emergent features of self-assemblies at the mesoscale.

PRE 2024 | PRX 2023 | Soft Matter 2023 | PRR 2022 | NJP 2022 | ACS Nano 2022 | Nat Mater 2017 | JCP 2016

 

 

Snapshot of a simulation model of trinagular particles self-assembling into a mesoporous gyroid surface.

Programmable self-assembly

Inspired by the remarkable array of functional assemblies of living systems, as well as recent advances in design and fabrication of protein-like programmable subunits (e.g. DNA origami & de novo protein design), we seek basic principles for encoding arbitrarily complex structure and function into the self-assembling subunits as well as physical limits of programmable self-assembly itself.

ACS Nano 2024 | Sci Adv 2024 | PNAS 2024 | PNAS 2022 | RMP 2021

 

 

Sequence of helically-spiral and densely packing filaments possessing elliptical cross-sections.

Filamentous matter

Our research explores generic physical properties of filamentous matter, a broad class which encompasses biological and synthetic nanostructured materials, ranging from carbon nanotubes and assemblies of interconnected long chain-like molecules, to filamentous proteins within and around biological cells, and even to steel cables to textiles at the macroscale . We study theoretical models of multi-filament material structures and related phenomena that derive from the generic, yet poorly understood, interplay of their one-dimensional intra-filament shape and multi-filament organization.

NJP 2024 | Nat Comm 2023 | PRL 2021 | Nat Comm 2020 | Soft Matter 2020 | NJP 2019 | PRL 2019 | PRX 2018 | Nat Mater 2016 | RMP 2015

 

Simulated hexagonal crystal conforming to a spherical surface.

Morphology selection in 2D soft matter

From cell walls to atomic sheets, thin sheets and membranes abound in living and synthetic materials.  Because bending is especially soft in such structures they exhibit a rich variety of non-planar geometries.  Our research focuses on complex morphologies that form in 2D membranes as a result of geometric incompatibility between in-plane order (usually solid) and complex out-of-plane shapes, such as fluid-solid coexistence in giant unilamellar lipid bilayer vesicles.

Soft Matter 2024 | Nat Comm 2024 | Sci Adv 2021 | PRL 2019 | PNAS 2019 | PRE 2016 | PRL 2014

 

Model of double-network morphology of dibock copolymers.

Complex macromolecular mesophases

Supramolecular assembly into long-range ordered “soft crystals” occurs for nearly every class of soft molecular assembly, from surfactants in water and liquid crystals to so-called giant amphiphiles and block copolymers . Paradigmatic examples of this are the micellar lattice phases of amphiphilic molecules, in which groupings of molecules self-organized into spherical and columnar groupings, which in turn pack into higher order 2D or 3D ordered arrays.  Our research focuses on theoretical principles for understanding the emergence of complex symmetries and topologies of amphiphilic block copolymer assembly, particularly under conditions where favorable local packing is intermediate to simple spherical, cylindrical or spherical topologies, leading to complex polycontinuous network or self-alloying crystal morphologies.

PRL 2024 | J Poly Sci 2023 | PRM 2023 | Nat Comm 2022 | Macro 2021 | Nat 2019 | PNAS 2018 | PRL 2017

People

News from the Grason Research Group

More News from the Grason Research Group
Loading...

Group Publications

Support/Funding

  • We are grateful to acknowledge research funding from the following current and former sponsors:
    NSF - Division of Materials Research; Division of Civil, Mechanical and Manufacturing Innovation; Division of Chemical, Bioengineering, Environmental and Transports Systems
    NSF - Materials Research Science & Engineering Center (MRSEC); Nanoscale Science & Engineering Center (NSEC)
    ACS PRF - New Directions Program
    AFOSR AOARD
    Department of Energy - Basic Energy Sciences
    Alfred P. Sloan Foundation