The idea of this summer school is to create a friendly learning atmosphere, to enable open communication between students and lecturers, and create opportunities for students to make lasting contacts with peers at other universities.
Topics for 2020:
| Emanuela Del Gado, Georgetown University | Soft Amorphous Matter Soft condensed matter (proteins, colloids or polymers) easily form gels or amorphous soft solids, where rigidity emerges in diverse structures with a variety of mechanical features. Examples include glass, cement, compacted sand, and even yogurt or chocolate mousse. Through the interplay between their microstructure with an imposed deformation, these materials can be stretched, flow, squeezed or fractured. Controlling and being able to design such processes is of paramount importance in a number of technologies, such soft inks for 3D printing technologies or self-healing materials for soft robotics. This short course will provide an overview of the physics of these materials, starting from the solidification processes, which are typically sources of frozen-in stresses. We will discuss fundamental theoretical concepts, computational approaches and experimental quantification of the rich microscopic dynamics which enters the linear response, drives aging of their mechanical properties or couple to stress or strain localization. | |||
| Haim Diamant, Tel Aviv University | Sedimentation Sedimentation is the motion of objects through a viscous fluid when they are subjected to a unidirectional force. For colloidal objects sedimenting under gravity in water, the motion can be assumed inertialess. In this limit the object’s response to the force (its resulting linear and angular velocities) is immediate and linear, and thus fully characterized by a matrix of constant coefficients, the mobility matrix. Once the fluid’s viscosity and the object’s typical size are scaled out, the mobility matrix of an isolated object depends only on the object’s shape and its orientation with respect to the force. For example, the mobility of an isolated sphere in an unbounded fluid is proportional to the identity matrix, independent of orientation, with a prefactor given by the Stokes formula.
The simplicity of that well-known example, however, is misleading. First, despite the instantaneous linear response, the equation of motion of a sedimenting, arbitrarily shaped object is nonlinear. This is because the mobility matrix depends on orientation, and the change of orientation (angular velocity) depends on the mobility matrix. Second, if there are two or more objects, their motions are coupled over large distances via the fluid’s flow (hydrodynamic interaction). Thus sedimentation is a driven, nonlinear, strongly correlated phenomenon. This mini-course will review the physical principles of sedimentation and their consequences. It will not be a course in fluid dynamics and will hardly consider objects of specific shape. We will concentrate instead on generic properties and effects arising from symmetries and conservation laws and pertaining to objects of arbitrary shape. The mini-course will discuss the following topics:
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| Greg Grason, University of Massachusetts Amherst | Self-limiting Assembly Self assembly is a ubiquitous process in soft matter, broadly defined as the spontaneous self-organization of multiple subunits (e.g. macromolecules, particles) into a coherent multi-unit structures. In the far most common class of scenarios, equilibrium assembly only gives rise to two “states”: a dispersed state of disassociated units; or otherwise, a bulk-condensed state of unlimited spatial dimensions. The focus of these lectures will be on the basic principles of the more specialized class of self-limiting assemblies, which refers to equilibrium assembly processes resulting in finite size structures. These systems pose a basic question, how do thermodynamic processes defined by non-covalent interactions between identical subunits “measure” and select the size of assembled structures? The lectures will introduce a basic statistical framework for assembly thermodynamic, and more specifically, use this to highlight the key physical ingredients of equilibrium assembly that terminate a finite dimensions. Examples of physical self-limiting assembly systems will be introduced and classified within this framework. These will include well-known cases in biology and synthetic soft matter of micellization of amphiphiles and shell/tubule formation of tapered subunits, as well as still poorly understood classes assemblies, such as, short-range attractive/long-range repulsive systems and geometrically-frustrated assemblies. |
Format: Due to the covid-19 situation, the 2020 Summer School will be held as a 5-day online event running from noon on Sunday, May 31 to Thursday Evening, June 4, 2020. Three lecturers will give mini-courses composed of three or four 75-min lectures, plus additional time for discussion. The lectures will be interspersed with opportunities for student presentations, and some online social activities. The Summer School will tentatively run from 10:30am to 4:00pm, Eastern time each day to enable remote participants from as many areas as possible. The detailed daily schedule will be posted soon, under the “Schedule 2020” tab.
Sound bites: All participants are encouraged to present a short “sound bite” describing the research they are involved in or going on in their research groups. These sound bites do not need to report new or finished research results, and can be less formal than talks you would present at a regular conference. We will have several sessions of these sound bites, where you can find out about what is happening at other universities.