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Publications

ATRP Enhances Structural Correlations In Polymerization-Induced Phase Separation**

Cornell Affiliated Author(s)
Author
A. Sicher
R. Whitfield
J. Ilavsky
V. Saranathan
A. Anastasaki
E.R. Dufresne
Abstract

Synthetic methods to control the structure of materials at sub-micron scales are typically based on the self-assembly of structural building blocks with precise size and morphology. On the other hand, many living systems can generate structure across a broad range of length scales in one step directly from macromolecules, using phase separation. Here, we introduce and control structure at the nano- and microscales through polymerization in the solid state, which has the unusual capability of both triggering and arresting phase separation.

Journal
Angewandte Chemie - International Edition
Date Published
Funding Source
DE‐AC02‐06CH11357
Group (Lab)
Eric Dufresne Group

Siloxane Molecules: Nonlinear Elastic Behavior and Fracture Characteristics

Cornell Affiliated Author(s)
Author
T. Li
E.R. Dufresne
M. Kröger
S. Heyden
Abstract

Fracture phenomena in soft materials span multiple length and time scales. This poses a major challenge in computational modeling and predictive materials design. To pass quantitatively from molecular to continuum scales, a precise representation of the material response at the molecular level is vital. Here, we derive the nonlinear elastic response and fracture characteristics of individual siloxane molecules using molecular dynamics (MD) studies. For short chains, we find deviations from classical scalings for both the effective stiffness and mean chain rupture times.

Journal
Macromolecules
Date Published
Group (Lab)
Eric Dufresne Group

Hydroelastomers: soft, tough, highly swelling composites

Cornell Affiliated Author(s)
Author
S. Moser
Y. Feng
O. Yasa
S. Heyden
M. Kessler
E. Amstad
E.R. Dufresne
R.K. Katzschmann
R.W. Style
Abstract

Inspired by the cellular design of plant tissue, we present an approach to make versatile, tough, highly water-swelling composites. We embed highly swelling hydrogel particles inside tough, water-permeable, elastomeric matrices. The resulting composites, which we call hydroelastomers, combine the properties of their parent phases. From their hydrogel component, the composites inherit the ability to highly swell in water. From the elastomeric component, the composites inherit excellent stretchability and fracture toughness, while showing little softening as they swell.

Journal
Soft Matter
Date Published
Group (Lab)
Eric Dufresne Group

The effect of surface-active statistical copolymers in low-energy miniemulsion and RAFT polymerization

Cornell Affiliated Author(s)
Author
M. Rolland
E.R. Dufresne
N.P. Truong
A. Anastasaki
Abstract

Low-energy miniemulsions enable the production of uniform nanodroplets for a wide range of applications without the need for using specialized equipment. However, low-energy miniemulsions are typically formed in the presence of a surface-active agent with a specific structure and property.

Journal
Polymer Chemistry
Date Published
Funding Source
DE180100076
DP200100231
Group (Lab)
Eric Dufresne Group

Geometrical frustration of phase-separated domains in Coscinodiscus diatom frustules

Cornell Affiliated Author(s)
Author
Maria Feofilova
Silvan Schüepp
Roman Schmid
Florian Hacker
Hendrik Spanke
Nicolas Bain
Katharine Jensen
Eric Dufresne
Abstract

Diatoms are single-celled organisms with a cell wall made of silica, called the frustule. Even though their elaborate patterns have fascinated scientists for years, little is known about the biological and physical mechanisms underlying their organization. In this work, we take a top-down approach and examine the micrometer-scale organization of diatoms from the Coscinodiscus family. We find two competing tendencies of organization, which appear to be controlled by distinct biological pathways. On one hand, micrometer-scale pores organize locally on a triangular lattice.

Journal
Proceedings of the National Academy of Sciences
Date Published
Research Area
Group (Lab)
Eric Dufresne Group

Evolution of single gyroid photonic crystals in bird feathers

Cornell Affiliated Author(s)
Author
Vinodkumar Saranathan
Suresh Narayanan
Alec Sandy
Eric Dufresne
Richard Prum
Abstract

Vivid, saturated structural colors are conspicuous and important features of many animals. A rich diversity of three-dimensional periodic photonic nanostructures is found in the chitinaceous exoskeletons of invertebrates. Three-dimensional photonic nanostructures have been described in bird feathers, but they are typically quasi-ordered. Here, we report bicontinuous single gyroid β-keratin and air photonic crystal networks in the feather barbs of blue-winged leafbirds ( Chloropsis cochinchinensis sensu lato ), which have evolved from ancestral quasi-ordered channel-type nanostructures.

Journal
Proceedings of the National Academy of Sciences
Date Published
Funding Source
CRP20-2017-0004
R-607-265-241-121
DE-AC02-06CH11357
Research Area
Group (Lab)
Eric Dufresne Group

Sustained enzymatic activity and flow in crowded protein droplets

Cornell Affiliated Author(s)
Author
Andrea Testa
Mirco Dindo
Aleksander Rebane
Babak Nasouri
Robert Style
Ramin Golestanian
Eric Dufresne
Paola Laurino
Abstract

Living cells harvest energy from their environments to drive the chemical processes that enable life. We introduce a minimal system that operates at similar protein concentrations, metabolic densities, and length scales as living cells. This approach takes advantage of the tendency of phase-separated protein droplets to strongly partition enzymes, while presenting minimal barriers to transport of small molecules across their interface.

Journal
Nature Communications
Date Published
Funding Source
GR19106
P19764
172824
Research Area
Group (Lab)
Eric Dufresne Group