Speaker: Christine Ortiz Associate Professor of Materials Science and Engineering Date: Friday, September 26, 2008 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:40am ) Location: The Chipman Room (6-104)

Biological materials, such as musculoskeletal tissues, have developed amazingly complex, hierarchical, heterogeneous nanostructures over millions of years of evolution in order to function properly under the mechanical loads they experience in their environment. In this talk, I will describe studies of these fascinating materials using "nanomechanics"; i.e. the measurement and prediction of extremely small forces within and between nanoscale constituents in order to provide a fundamental molecular-level understanding of the mechanical function, quality, and pathology of structural biological materials. Examples of materials under investigation to be discussed include; cartilage and bone. A quad-tiered approach is taken in order to achieve this goal which includes; nanomechanics of single cells and their pericellular matrix, individual extracellular matrix molecule imaging, biomimetic model systems, and tissue-level properties. Nanotechnological methods applied to the field of musculoskeletal tissues and regenerative medicine (e.g. stem-cell based tissue engineering) hold great promise for significant and rapid advancements towards tissue repair and/or replacement and improved treatments for people afflicted with diseases such as osteoarthritis.

Speaker: Edwin (Ned) Thomas Morris Cohen Professor Materials Science and Engineering Department Head Date: Wednesday, April 16, 2008 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:40am ) Location: The Chipman Room (6-104)

Nanotechnology requires control of materials from the atomic to the 100 nanometer to the macroscopic level. Exploiting the size and shape dependence of material properties and accessing multi-functionality holds great promise for the development of materials that will contribute to novel future technologies. Polymers are a class of materials that have a very broad range of properties and moreover, can act as hosts for metallic and dielectric nanoparticles as well as organic molecules, resulting in nanocomposites with combinations of properties not available by other means. Periodic structural assemblies are of particular interest, due to their interesting interactions with waves: especially electromagnetic and mechanical waves. Progress in this exciting area requires excellent control of structure formation. A top-down, bottom-up approach, involving interference lithography and self assembly is demonstrating good success in fabricating the requisite structures and desired properties for photonics and phononics.

Speaker: Markus Buehler Professor of Civil and Environmental Engineering Department of Materials Science and Engineering Lecturer Date: Thursday, March 20, 2008 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:40am ) Location: The Chipman Room (6-104)

After identifying the entire genetic code of several species, it is now apparent that the ultimate frontier in the life sciences lies beyond identifying the sequence of DNA. The next grand challenge is the understanding of the multi-scale behavior of hierarchical protein assemblies, that is, the elucidation of the interface between structure and material. The advancement of this field is crucial for studies of biological systems, disease diagnosis and treatment, as well as the design of novel materials. Proteins constitute critical building blocks of life, forming materials such as hair, bone, skin, spider silk or cells, which play a key role in providing important mechanical functions in biology. The fundamental deformation and fracture mechanisms of biological protein materials, however, remain largely unknown, partly due to a lack of understanding of how protein building blocks respond to mechanical load and how they participate in the deformation and function of the overall biological system. The mechanics of protein materials is vital for models of diseases, the understanding of tissue injuries, for models of biological processes such as mechanotransduction, and the development of biomimetic and bioinspired materials. In this talk we review atomistic molecular dynamics simulations implemented on supercomputing facilities, combined with continuum mechanical and statistical theories, used to develop predictive models of the deformation and fracture behavior of protein materials. This approach explicitly considers the hierarchical architecture of proteins, including the details of their chemical bonding, capable of predicting their unfolding behavior and thereby providing a structure-property relationship. We review the development of a fracture theory and strength model for beta-sheets and alpha-helices, two prominent protein motifs that form the basis of many protein materials, including spider silk and intermediate filaments. Our studies elucidate intriguing material concepts that facilitate to balance strength, dissipation and robustness via nanopatterned hierarchical features. Our results suggest universal scaling laws that govern the mechanical response of protein structures. We discuss these observations in light of a newly proposed universality-diversity paradigm, which is based on the idea that the key to understand the properties of protein materials is to consider the interplay of universal structural features and a set of highly diverse features. It is found that this viewpoint can be applied to numerous classes of protein materials, thereby providing a fundamental perspective to explain the evolutionary footprint of structural protein materials. We discuss the implications of our work for materials science, biology, the science of multi-scale interactions, and how this knowledge can be exploited to develop new bioinspired materials and structures.

Speaker: Caroline Ross Professor of Materials Science and Engineering Date: Monday, October 22, 2007 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:40am ) Location: The Chipman Room (6-104)

Nanoscale magnetic materials are the basis of magnetic data storage devices such as hard drives and magnetic random access memories. As these devices evolve, there is an increasing need to understand nanoscale magnetic properties of materials, and develop ways to fabricate them. In this talk I will describe methods based on self-assembly of block copolymers, as well as more conventional lithography methods, to fabricate arrays of nanomagnets, and show how these materials may be used in future data storage devices.

Speaker: Eugene Fitzgerald Merton C. Flemings-SMA Chair Professor of Materials Engineering Date: Tuesday, May 15, 2007 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:40am ) Location: The Chipman Room (35-410)

Strained silicon has had a significant role in extending Moore’s Law, which is the increase of transistor density in silicon integrated circuits as time passes.  New materials have recently played an increasingly important role in one of the most important sectors for the economy (information technology).  But will new materials advances allow us to continue on previous industry trajectories?  If not, is there new opportunity?  And finally, how will innovations in materials find their way in the current industry structure to deliver the most value in the marketplace?

Speaker: Lionel C. Kimerling Thomas Lord Professor in Materials Science and Engineering Director of the MIT Materials Processing Center Director of the MIT Microphotonics Center Date: Tuesday, May 1, 2007 Time: 12:00pm-1:00pm (pizza and refreshments will be served at 11:30am ) Location: The Chipman Room (35-410)

The optical components industry stands at the threshold of a major expansion that will restructure its business processes and sustain its profitability for the next three decades. This growth will establish a cost effective platform for the partitioning of electronic and photonic functionality to extend the processing power of integrated circuits and the performance of optical communications networks. The traditional dimensional shrink approach to the scaling of microprocessor technology is encountering barriers in materials and power efficiency that dictate more distributed architectures. This direction will ignite a major change in leadership of the industry from information transmission (telecom) to information processing (computing, imaging); and it will open significant new markets with high volume applications. The talk will present an overview of the challenges and the roles of materials and process design in fomenting the revolution.