E-mail: blair [at] physics [dot] georgetown [dot] edu
Professor Daniel Blair received his PhD in Physics from Clark University after obtaining a SM from the University of Chicago. Prior to his graduate work professor Blair spent over a year as a research student at Argonne National Laboratory in the Material Science Division. After receiving his PhD in 2004, he was a postdoctoral fellow in the School of Engineering and Applied Sciences and the Department of Physics at Harvard University with David Weitz. Professor Blair received a National Science Foundation Faculty Early Career Development (CAREER) award in 2009.
Professor Blair's work can be described as soft condensed matter physics. Soft matter or soft materials physics is a young subfield of condensed matter physics that has it's roots in polymer science. Specifically, his group is working to understand the link between the microstructure of disordered materials and their bulk mechanical properties. To accomplish this, his group is performing experiments in which they deform and measure stress propagation in soft disordered solids such as colloidal glasses, gels, and foams. The glasses we construct are surprisingly similar to their atomic counterparts, but have length and size scales that allow for direct real time information to be acquired using advanced microscopy techniques.
Soft Glassy Solids
The Blairlab is interested understanding the structural behavior of glasses. Glasses are found nearly everywhere in nature and industry. Despite their ubiquity and an intensive study of their properties, the underlying physical mechanisms responsible for the glass transition remain poorly understood. Many soft materials, such as colloidal dispersions, exhibit behavior indicative of the glass transition. In fact, colloidal glasses exhibit many of the hallmarks associated with glasses, such as aging and heterogeneous dynamics.
In the Blairlab we utilize tools such as confocal microscopy and rheology (bulk and micro) to investigate the micromechanical structure and properties of soft glassy solids. Specifically, we investigate the spatial distribution of forces inside colloidal emulsions under shear stress. By compressing the emulsion drops, we can pick out the contact forces directly and measure how the spatial structure of those forces is changed under the application of shear. This work will provide unprecedented information into the way structurally disordered solids undergo mechanical failure.
We are also using thermally sensitive hydrogel particles to understand the onset of glassy behavior in colloidal glasses. Our contention is that the mechanical properties of the glass must be determined through the interplay between the microstructure and the particle level dynamics as the transition is crossed. To investigate these ideas, we utilize three dimensional confocal microscopy linked with bulk rheology to investigate the glassy dynamics and heterogeneous particle restructuring events under external shear. This system will allow us to deﬁnitively quantify how the inherent glassy structure affects the rheological properties of amorphous solids.
Professor Blair is currently using these methods to investigate the distribution of forces inside of strained biopolymers. The goal of this work is to build up our knowledge of how networks of branched and cross-linked biopolymers distribute globally and locally applied strains. This will assist in understanding the varied morphologies found in cells and tissues that interact with the extracellular matrix.
Spring 2013: PHYS-152 (Electromagnetic Phenomena)
- "Cyclic hardening in bundled actin networks", K.M. Schmoller, P. Fernandez , R.C. Arevalo, D.L. Blair, and A.R. Bausch, Nature Communications, 1, 134 (2010).
- Size dependent rheology of type-I collagen networks, Richard C. Arevalo, Jeffey S. Urbach and Daniel L. Blair, Biophysical Journal, 99, L65-L67, (2010).
- T. Yu, R. Weiss, D. L. Blair, K. Wakuda, Reversibly crosslinking amino polysiloxanes by simple triatomic molecules. Facile methods for tuning thermal, rheological, and adhesive properties, J. Phys. Chem. C, 113, 11546 (2009).
- R. Weiss, A. V. Mallia, D. L. Blair, M. George, Nitrogen containing derivatives of (R)-12-hydroxystearic acid as gelators. Comparisons with stearic acid derivatives and some unprecedented structural and rheological properties of the organogels, Langmuir, 25, 8615 (2009).
- M. Caggioni, P. T. Spicer, D. L. Blair, S. E. Lindberg, and D. A. Weitz, Rheology and microrheology of a microstructured fluid: The gellan gum case, Journal of Rheology 51, 851 (2007).
- H. M. Wyss, D. L. Blair, J. F. Morris, H. A. Stone, and D.A. Weitz, Mechanism for clogging of microchannels, Phys. Rev. E 74 061402 (2006).
- D. L. Blair and A. Kudrolli, Geometry of crumpled paper, Phys. Rev. Lett. 94, 166107 (2005).
- D. Blair and A. Kudrolli, Magnetized Granular Materials, The Physics of granular media, H. Hinrichsen and D.E. Wolf (Editors) (Wiley-VCH publishers, 2004) 281-296.
- D. L. Blair, T. Neicu, and A. Kudrolli, Vortices in vibrated granular rods, Phys. Rev. E 67, 031303 (2003).
- D. L. Blair and A. Kudrolli, Clustering transitions in vibrofluidized magnetized granular materials, Phys. Rev. E 67, 021302 (2003).
- D. Blair and A. Kudrolli, Collision statistics of driven granular materials, Phys. Rev. E 67, 041301 (2003).
Professor Blair's research is funded by the National Science Foundation, the Petroleum Research Fund and the Air Force Office of Scientific Research (AFOSR).