The Harvard Materials Research Science and Engineering Center (MRSEC) is the focus of interdisciplinary research at the University. The participants of the MRSEC are drawn from five departments, including the Division of Engineering and Applied Sciences (DEAS); the Departments of Chemistry and Chemical Biology (Chemistry), Physics, Earth and Planetary Sciences (EPS); and the Medical School (HMS). The MRSEC is centered in DEAS, an ideal home for an interdisciplinary enterprise; DEAS has no departments, providing a strong incentive for interdisciplinary research. Harvard is encouraging interdisciplinary research and education, and the MRSEC is leading this new effort.

This is a time of significant renewal of materials research at Harvard, in both faculty and research infrastructure; the MRSEC both benefits from this, and contributes to this growth. The Harvard MRSEC is receiving strong institutional support from the University as the long-standing enterprise for interdisciplinary research, particularly from the Center for Imaging and Mesoscale Science (CIMS), a university-funded initiative aimed at improving the research infrastructure at Harvard. CIMS provided substantial support for major capital equipment for research, all of which is available to MRSEC participants. In addition, new support staff have recently been hired to maintain and operate the equipment, and to provide instruction in its use for MRSEC participants. The MRSEC contributes funds for both capital equipment and for technical assistance; this ensures that the MRSEC has a major role in the directions of CIMS, and provides very significant leverage of the MRSEC funding. In addition, a new laboratory that will house CIMS, and MRSEC-related faculty, has just been approved, ensuring that construction will begin in the near future. The MRSEC also received generous aid from DEAS and from the Faculty of Arts and Sciences (FAS) for laboratory renovation for shared experimental facilities as well as laboratory renovation and instrumentation for new MRSEC faculty. This support has enabled the MRSEC to embark in new directions while maintaining strength in existing areas of Materials Science and Engineering.

The MRSEC is organized into three Interdisciplinary Research Groups (IRGs):

IRG 1: Multiscale Mechanics of Films and Interfaces (Coordinator: Spaepen): This IRG builds on very successful and innovative studies of the properties of thin films, at scales intermediate between atomistic and continuum. Vlassak and Spaepen have developed new in situ experimental techniques to measure elastic properties of thin films, by monitoring surface curvature. They will extend this study to thin polymer films important in photoresist applications, and Hutchinson will assist in modeling their data. Polymer films are amorphous, and will not have the lattice dislocations that dominate the behavior of crystalline films. Weitz and Spaepen have used template-assisted growth to form high-quality single colloidal crystals. They will use these crystals as an “analog computer,” where each colloid models an atom in a traditional solid, and will investigate their behavior under shear by imaging them with a confocal microscope. Aziz and Golovchenko are investigating the stresses when ion and energetic atom beams are used to sculpt structures in thin films; this knowledge is essential to fully exploit focused ion beams in structure fabrication. Weitz is collaborating with Hutchinson and Xie to investigate the crack formation of thin films of colloidal particles as they dry. They have developed a scaling picture of the behavior that unifies data from many different samples, and are using this to investigate fluid flow through very narrow channels.

IRG 2: Engineering Materials and Techniques for Biological Studies at Cellular Scales (Coordinator: Whitesides): This IRG is focused on understanding the mechanical properties of the cell, a central object of study in biology, and its structural components. Tools and techniques necessary to study problems in biology at the scale of a single cell are being developed using the materials expertise of MRSEC participants. These include single-molecule imaging (Zhuang, Xie) and particle-tracking (Weitz) techniques to probe the dynamics of molecules within cells and the structure and properties of their local environments. Prentiss is collaborating with Whitesides and Ingber to manipulate small particles with applied magnetic fields to probe the properties of cells. Ingber is also working with Whitesides to treat patterned surfaces to investigate the effect of the local environment on cells, and to use microfluidic channels to dose selected portions of individual cells with an external signal; Stone provides essential theoretical support in the design of the microfluidic devices. Mazur and Ingber are using focused lasers to perform microsurgery on cellular elements in order to probe their function and mechanics. The ultimate goal of this research will be the development of a sophisticated set of tools for investigation of the mechanical properties and functions of the cell.

IRG 3: Interface-Mediated Assembly of Soft Materials (Coordinator: Brenner): This new IRG will explore innovative ways to make self assembly of soft materials more generally useful by using interfaces as templates for growth. Theoretical work of Nelson motivates the investigation of the fascinating behavior of packing of small repulsive particles on a spherical surface. Weitz has experimentally investigated repulsive particles on curved surfaces and has confirmed the theoretical predictions of Nelson. Small solid particles packed on a spherical surface can form rigid shells that have important potential applications for drug delivery, and Edwards and Weitz are using spray drying to form these shells. They are working with Brenner and Hutchinson to explore their unusual mechanical properties. Coulomb interactions between particles in non-aqueous media are being explored experimentally (Weitz) and theoretically (Brenner). Close collaboration with Morrison (Cabot) provides an industrial link to possible applications. New techniques for highly controlled synthesis of single objects are being explored by Stone, Weitz and Whitesides who are using microfluidic devices to direct the assembly; Brenner is providing further theoretical support. This IRG is highly leveraged with industrial support.

Seed Project: Initiative on Functionalized Interfaces (Coordinator: Friend): We have established a new initiative as a large-scale seed project; if it is successful, it will evolve into a full IRG during the course of the grant. The initiative is on functionalized interfaces, and its goal is to investigate both the synthesis and properties of such interfaces to create new structures that may ultimately have important technological applications. Gordon is using alternating layer deposition to create very high quality coatings that have large dielectric constants and can sustain high fields; Marcus will use these in devices to inject charge using high electric fields. Friend is working with Whitesides, Aziz and Mazur to create ordered arrays of microstructured surfaces which have important potential for field emission and molecular binding for sensor applications. Martin is collaborating with Friend to develop chemical tools for shaping interfaces on length scales ranging from nanometers to microns using agent directed precipitation and dissolution. Whitesides and Prentiss are developing new organic interfaces for charge storage and transfer.

Interdisciplinary education in materials research is a cornerstone of the Harvard MRSEC. This includes a the broad set of educational programs, including summer research experience for undergraduates and teachers, programs for seventh grade students in the very diverse Cambridge public school system, public lectures at the university and at local museums. Two new initiatives are aimed at increasing participation of underrepresented groups: A special MRSEC postdoctoral program for women and minorities and a new program to actively recruit minority students and faculty for MRSEC-related research. In addition, the Center plays a key role in establishing and running the quarterly New England Complex Fluids Workshops, which provide an invaluable venue for interactions with the local community, with members of other MRSECs and with scientists in industry and teaching colleges.

Shared experimental facilities provide sophisticated instrumentation for materials preparation and characterization, coupled with professional guidance and technical support, to Center participants and outside users from academia and industry. Facilities include the Cambridge Surface Facility, Electron Microscopy, Cleanroom, Materials Preparation and Mechanical Testing. In addition, the facilities established by the Harvard-University-sponsored Center for Imaging and Mesoscale Structures (CIMS) include an expanded Electron Microscope Facility and an expanded Cleanroom Facility in the Gordon McKay Laboratory. In addition, CIMS has purchased a significant amount of new equipment that directly benefits the MRSEC and that is available to all MRSEC participants. This includes a coherent anti-Sokes Raman scattering microscope, a two-photon confocal microscope, a microscope dedicated to the study of live cells as well as extensive deposition and imaging equipment.

Collaborations with industry, national laboratories, and other institutions are actively pursued. DEAS sponsored an Industrial Outreach Program (IOP) with a meeting held at Harvard to bring representatives from industry and government labs to the university to learn about the science being done by MRSEC investigators, and to encourage further interactions. The MRSEC continues to sponsor the Quarterly New England Complex Fluids Workshops, which brings together researchers from other MRSECs, academic institutions and from local industry. Dr. Peter Kaplan, who gave a keynote address at the 14th Complex Fluids Workshop, also joined the Center as a MRSEC Distinguished Industrial Visitor with support provided by industry. The Center also has close ties with the Rowland Institute of Science in Cambridge, which recently became part of Harvard; Spaepen is the Scientific Director.