Fundamental Issues in Materials Integration on Silicon investigates the fundamental atomistic and mesoscopic mechanisms underlying the integration of materials, devices and structures on silicon, as an integration platform. Materials integration on Si leverages the power of CMOS through the addition of other components, thereby increasing function while maintaining the advantages and the versatility of Si processing and device technology. This research provides the foundation for development of vastly enhanced and totally new electronic devices. The MRSEC enables the assembly of broad expertise that allows us to address the detailed structural, chemical, and electronic issues underlying heterogeneous integration. Si is used as the model of a multi-functional material: as an integration platform, a template for growth of nanoscale structures, a mechanical element, and a semiconductor.

IRG Senior Participants: Darrell Schlom (co-leader, Mat Sci), Kyle Shen (co-leader, Phys), Joel Brock (Appl Phys), J.C. Séamus Davis (Phys), Craig Fennie (Appl Phys), Richard, E.-A. Kim (Phys) G. Hennig (MatSci), David Muller (Appl Phys)
Collaborators: M. Lawler (SUNY Binghamton)

Our group aims to study and control complex electronic materials -- systems where strong quantum interactions can result in unexpected and novel phenomena, including superconductivity, high thermopower, unconventional magnetism, and metal-insulator transitions. The physical properties of these complex electronic materials will be finely tuned through a variety of approaches including epitaxial strain, chemical doping, and interfacial engineering. These materials will be characterized using various probes of the electronic structure, both in real-space (STM, STEM) and momentum-space (ARPES, x-ray scattering), which will provide valuable input into developing realistic theoretical models for these novel and exciting systems.

The vision of IRG-3, Hierarchical Multifunctional Macromolecular Materials, is to develop a multiple interaction approach to polymer materials design that enables multifunctional applications by decoupling the optimization of two or more desired attributes. The IRG will explore this paradigm in three integrated thrusts that aim to: (i) control aqueous rheology and gelation with polymers containing cellulose ether blocks; (ii) control the structure and properties of block-polymer-based "amphiplexes", assemblies of polyanions with cationic copolymer micelles; and (iii) design and prepare novel multiblock polymers featuring independent control of ordered-state symmetries and mechanical properties. Intellectual advances by the IRG will impact a wide range of societally important technologies, including batteries, composites, food, fuel cells, lithography, oil and gas recovery, personal care, pharmaceutical formulations, textiles, water purification and treatment.

IRG Senior Participants: Héctor Abruña (C&CB, co-leader), Dan Ralph (Phys, co-leader), Piet Brouwer (Phys), Robert Buhrman (A&EP), J. C. Séamus Davis (Phys), Paul McEuen (Phys), David Muller (A&EP), Sandip Tiwari (ECE), R. Bruce van Dover (MS&E) Collaborators: G. Coates (Cornell); W. Harneit (Freie Universität Berlin); C. W. Kim, M. K. Kim (Samsung Electronics); D. N. Hendrickson (UCSD); J. R. Long (Berkeley); H. Park (Harvard); C. Timm (Univ. of Kansas) Our group is working to achieve atomic-level understanding and control of the electronic properties of interfaces, so as to better manipulate electron and spin transport. By combining advanced microscopy techniques with state-of-the-art nanofabrication and chemical synthesis, we are conducting fundamental research into the coupling between metal electrodes and molecules in single-molecule devices. We are also investigating the charge states at insulating interfaces that are used for molecular electronics, magnetic tunnel junctions, and silicon devices.

The Materials Research Science and Engineering Center (MRSEC) at the University of Massachusetts Amherst supports an interdisciplinary program in the area of polymeric materials. The Center is entitled "Materials Research Science and Engineering Center on Polymers".

The research is organized into three interdisciplinary research groups (IRGs). Tailored Interfaces (IRG 1) focuses on controlling the lateral order in thin polymer films using a variety of chemical, surface structural, and applied field techniques. IRG 2 on Structured Materials in Supercritical Fluids is concerned with the incorporation of supercritical CO2 in polymers with emphasis on gaining a fundamental understanding (diffusion, thermodynamics, interfacial interactions) of the process. Aqueous Polymer Assembly (IRG 3) investigates the assembly of polymers in aqueous solutions. The goal is to understand the contributions of various forces (electrostatic, hydrophobic, hydrodynamic, etc) in order to predict the final nano structured material.

The Center has active education and outreach programs with special emphasis on undergraduate and K-12 teacher education. Effective links to the liberal arts colleges for women (Smith and Mount Holyoke) have been established. A total of 8 undergraduates will be sponsored at Smith and Mount Holyoke. Other ties to undergraduates are developed through faculty links at Howard U. and Harvey Mudd College. The Center's outreach to colleges is leveraged by a NSF Research Site on Education in Chemistry award (RSEC) with Smith, Mount Holyoke and Amherst Colleges.

The MRSEC operates eleven shared experimental facilities which are also an effective tool in the education outreach program. The Center has a well developed industrial oureach program. The Center for UMass-Industry Research on Polymers (CUMIRP) leverages the MRSEC's outreach efforts by linking industrial sponsors with UMass research programs, faculty, and students. CUMIRP also fosters education links to industry in the form of the industrial visitors program (several week visits by industrial scientists at UMass), industrial scientist speaker program, and participation of industrial scientists on dissertation committees.

IRG 1 pioneers endotaxial heterostructures—interleaved polytypes of 2D materials—to access novel quantum states for advanced computing. By combining computational predictions, synthesis techniques, and device fabrication, this research enables breakthroughs in quantum and classical information technologies, aligning with priorities in nanoelectronics and quantum science.

IRG 2 explores materials capable of withstanding extreme temperatures and pressures for nuclear fusion and hypersonic defense systems. Through neutron scattering, AI, and materials co-design, the group advances the understanding of structure, stability, and properties, driving innovations in energy, transport, and security technologies.

Principal Investigator
Pierre-Thomas Brun, Assistant Professor of Chemical and Biological Engineering (CBE)

Seed start and end dates: November 1, 2018 - October 31, 2019

Natural soft materials are often architected at all scales, and shaped in periodic structures that achieve advanced functionalities which cannot be matched by man-made materials [1–3]. Adapting these concepts to our own technological needs requires the development of a new fabrication pathways to structure and shape soft materials. The research objective of this project is to devise and formalize a new class of topologically and hierarchically architected soft materials (ASM) using interfacial instabilities. Our ASM consist of silicone based elastomers patterned with liquid inclusions whose shape, arrangement and composition is programmed using the rules and tools of fluid mechanics. Specifically, the Rayleigh-Plateau instability (RPI) is harnessed in viscous threads printed in polymer melts that cure in finite time so as to ’freeze’ the disperse phase and form tangible objects (see Fig1). The project is concerned with the directed control of these instabilities to robustly fabricate and control the size, the arrangement, and the morphology of our ASM.

While instabilities are traditionally regarded as a route towards failure in engineering, the PI aims to follow a different path; taming fluidic instabilities and harnessing the patterns and structures they naturally form. This methodology, recently demonstrated by the PI in another problem[4], capitalizes on the inherent periodicity, scalability, versatility and robustness of instabilities. This new design paradigm – building with instabilities – calls for an improved understanding of instabilities and pattern formation in complex media. Stability analysis is a classic topic in fluid mechanics, yet, little is known on the so called inverse problem: finding the optimal set of initial conditions and interactions that will be transmuted into a target shape without direct external intervention. More broadly, the project is rooted on the basis of recognizing model experiments as a valuable and powerful tool for discovery and exploration, in turn seeding the development of formal and predictive models.

IRG-1 aims to establish cell-free bioprogrammable materials, a new class of bioinspired composites whose properties autonomously adapt in response to specific spatiotemporal cues via the collective activity of embedded artificial cells. These bioprogrammable materials will possess autonomous properties such as self-healing, on-demand cargo release, degradation, dynamic mechanical property modulation, biomineralization, and shape-morphing. IRG-1 will establish a new paradigm for enhancing the performance and capabilities fo soft active materials by endowing them with the adaptive multi-functionality of biological systems, thus accelerating advances in sustainable agriculture, soft robotics, water treatment, smart clothing, food storage, and wound healing.