Frederick MacKintosh
Rice University, TX·Physics
Skin, organs and blood clots get their strength from tangled networks of protein fibers such as collagen and fibrin. Unlike rubber, these networks become stiffer and more stable the more they are stretched or deformed.
- Fields
Physics
Biophysics
Materials Science
- Topics
fiber networks
semiflexible polymers
biopolymer networks
- Grants
- 1 known grant, through Feb 2027
What they work on
- Develop a predictive effective medium theory, an averaging method that treats the network as a uniform material, for the strain-driven stiffening transition in 2D and 3D networks of stiff, athermal fibers such as collagen.
- Extend effective medium theory and computational models to thermal semiflexible polymer networks, exploring possible new phase behavior analogous to quantum critical systems.
- Study how active stresses, internal forces generated within the network, control the mechanics of semiflexible polymer networks.
- Build computational models of incompressibility in extracellular matrix, such as collagen–hyaluronic acid composites, to capture compression resistance missing from prior network models.
More about the research
The PI and collaborators have shown that this self-stiffening can be understood as a phase transition, much like water freezing into ice, except that it is triggered by deformation instead of cooling. Still, no theory of fiber networks yet predicts their behavior as reliably as classical theories of flexible polymers do. One reason is that collagen fibers are so stiff that random thermal motion barely affects them, so the usual heat-based explanations of elasticity do not apply.
Why it matters
A predictive theory of collagen and other fiber networks could improve understanding of how soft tissues bear loads, and of how joints resist compression through hyaluronic acid. It could also guide the rational design of synthetic materials with similar self-stiffening properties, for example for tissue engineering. The physics approaches may also apply to other soft materials.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Jeffrey Morris
CUNY City College, NY·Engineering
Characterize the particle contact networks that form during discontinuous shear thickening in simulated dense suspensions, across different flow types, solid fractions and particle-size mixtures.
Qimiao Si
Rice University, TX·Physics
Analyze quantum criticality in heavy fermion metals, where electrons behave as if very heavy, focusing on new regimes marked by singular charge responses near zero-temperature phase transitions.
Itamar Kolvin
Georgia Institute of Technology, GA·Physics·Early-career
Determine how active forces from kinesin motors walking on microtubules disrupt arrangements of bacterial flagellar filaments that would be stable under ordinary thermal motion.
The school
Rice University: 24 labs on PI Pages, $278M a year on research, 267 research doctorates a year.
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