Physics at Virginia

Lou Bloomfield

Ph.D., 1983, Stanford
Professor Emeritus

Experimental Atomic, Molecular, and Optical Physics,Experimental Chemical Physics,Experimental Condensed Matter Physics

Research Interests

Professor Bloomfield is studying borosilicones, remarkable materials that have been misunderstood for over 70 years. Dismissed as scientifically uninteresting and used as children's toys (e.g., Silly Putty), borosilicones are actually network liquids---dynamic macromolecules that appear elastic on short timescales but exhibit flow on longer timescales. Each borosilicone is a vast covalent network of silicone polymer chains joined by 3-attachment boron crosslinks. At any instant, a borosilicone is a highly-crosslinked elastic material. Because the boron crosslinks are temporary, however, the network evolves with time and the borosilicone exhibits liquid behavior. While the simplest borosilicones are elastic liquids, more complicated borosilicones are intermediate between elastic liquids and elastic solids. The dynamics of these non-simple borosilicones are well-described by differential equations of fractional-order (see fractional calculus). When the concentration of permanent crosslinks added to a borosilicone exceeds the gelation threshold, the borosilicone loses its ability to flow and becomes a viscoelastic silicone rubber (VSR). A VSRs is a dual-network system: a liquid network piggybacking on a solid network. It has an equilibrium shape dictated by the topology of its solid network, but exhibits the extreme viscoelastic behavior associated with its liquid network.

Selected Publications

Shape Recovery in Viscoelastic Silicone Rubber and the Fractional Zener Model (L. A. Bloomfield), arXiv:1912.08889 [cond-mat.soft] (2019).

Rapid technique for preparing conductive graphene-borosilicone putty (L. A. Bloomfield), arXiv:1912.02116 [cond-mat.soft] (2019).

Laminar Flow and Backrind Formation in Molding of Viscoelastic Silicone Rubber (L. A. Bloomfield), arXiv:1905.06313 [cond-mat.soft] (2019).

Borosilicones and Viscoelastic Silicone Rubbers: Network Liquids and Network Solids (L. A. Bloomfield), arXiv:1801.09253 [cond-mat.soft] (2018).

Viscoelastic silicone rubber compositions (L. A. Bloomfield), U.S. Pat. No. 9,550,864 (2017).

Viscoelastic silicone rubber compositions (L. A. Bloomfield), EP 2545103 (2016).

Viscoelastic silicone rubber compositions (L. A. Bloomfield), U.S. Pat. No. 9,102,799 (2015).

News Items

Congratulations to Lou Bloomfield for winning a 2021 All-University Teaching Award!  These awards recognize excellence in undergraduate, graduate, and/or professional teaching at UVA. Our ......More >
Professor Lou Bloomfield has posted a video explaining how social distancing can help to "flatten the curve" by ......More >
From Big Think: A great intro course that looks at physics in the context of everyday objects and processes. How does skating work? Why do things fall? The course uses ......More >
From NBC29: Trademarked as “MemorySil,” the shape-memory material is first being marketed as an earplug called EarJellies, referencing the jelly-like texture ......More >
From USA TODAY: "There's a tale we've all heard: A penny dropped from the top of the Empire State Building would fall at such a rate it would impale and kill anyone it ......More >
UVA physics professor Lou Bloomfield explains some of the fundamental forces at work in Olympic freestyle swimming, and how swimmers can use science to get ahead. More >
From UVaToday:"Professor Lou," as he is called on TV, is science central on a feature segment called "Forces of Hockey," which is produced by the Capitals and aired on the team's associated ......More >
From UVaToday:"If anything bothers University of Virginia physicist Lou Bloomfield, it's a wobbly table. So much so that he actually invented a material to eliminate the problem. The material, ......More >
From MSNBC:"The girl fell about 25 feet, which took about 1.25 seconds. The man stopped her fall in about 3 or 4 feet, which took about 0.1 second, depending on the stopping distance and how he ......More >
Prof. Bloomfield considers pennies from heaven (AKA the Empire State Building):'If it did strike you, it would feel like being flicked in the forehead — "but not even very hard," said Louis ......More >
From UVaToday:The Jefferson Scholars Foundation at the University of Virginia has awarded Louis A. Bloomfield its 2011 Faculty Prize. Bloomfield, a physics professor in the College of Arts & ......More >


APS Fellow [1994]
For seminal contributions to the understanding of magnetism in clusters.