MSE Department Seminar

WebEx link: https://rensselaer.webex.com/rensselaer/j.php?MTID=ma93dc36e9599786d8e7…

Glasses, as a disordered and non-equilibrium material system, do not have well-defined topological defects such as dislocations and grain boundaries.  For this reason glasses have many promising physical, chemical and mechanical properties in comparison to their crystalline counterparts, making them attractive for a wide range of applications. However, also due to the lack of order and disappearance of lattice periodicity, building a valid structures-properties relationship in glasses has been a longstanding challenge.

Thin films used in microelectronic and other microsystems are metastable.  If heated at sufficiently high temperatures they will agglomerate or dewet to form islands while remaining in the solid state.  The temperature at which solid state dewetting occurs decreases as the thickness of a film is decreased and dewetting can occur well below a material’s melting temperature.  The dewetting temperature also decreases as other dimensions are decreased, as in the case of the diameters of nanowires.  Scaling of feature sizes in microelectronic systems has led to increasing pro

2D material-based devices have received a great deal of attention as they can be easily stacked to obtain multifunctionality. With their ultrathin thicknesses, such multifunctioning devices become so flexible and conformal that they can be placed onto any 3D featured surfaces. However, 2D heterostructures are typically demonstrated as stacked flakes where single or few devices can be fabricated due to lack of strategies for layer-by-layer stacking of 2D materials at the wafer scale.

Polymers solvated by imidazolium salts exhibit better thermal stability and lower glass-transition temperature. Understanding the interactions and solvation between polymer and ionic liquid is important for designing soft and mechanically strong membranes with high ionic conductivity and thermal stability for their applications in electrochemical devices. In this talk, I will present our recent results about the structural and dynamic relations of poly(methyl methacrylate) (PMMA)-grafted nanoparticles in imidazolium-based ionic liquids.

Solid-state batteries (SSBs) are being considered as one of the most promising technologies for safer, high-energy, and long-term energy storage. However, key materials issues remain unsolved and serious barriers must be overcome for the full-scale commercialization of SSBs. In this presentation I will discuss some of our approaches to understand the key challenges in solid electrolyte materials.

The nano- to macro-scale physical and chemical properties of the environment that surrounds a cell play an important role in cell function and fate.

Sustaining local electric fields in confined microscopic environments as polarizing agents for catalyzing reactions is important. It is argued that many enzymes operate based on this principle and lessons learned from them can be extended to other catalytic systems. We use Stark shift spectroscopy to measure electric fields in electrochemical interfaces for understanding solvation, interfacial polarization, molecular structure, steric hindrance, and frustrated bond formation. We will present experimental results on fields at the junction of electrolytes and biased metal electrodes.

Silk fibroins are a class of proteins produced by a variety of insects and arachnids that can surpass man-made materials in specific strength and toughness. From a macromolecular perspective, silk fibroins have a linear architecture predominantly consisting of regularly alternating -sheet forming peptide segments and flexible peptide segments, resulting in a supramolecular network structure with stiff crystalline domains reinforcing an amorphous matrix.

Soft electronic devices that can acquire vital signs from the human body represent an important trend for healthcare. Combined strategies of materials design and advanced microfabrication allow the integration of a variety of components and devices on a stretchable platform, resulting in functional systems with minimal constraints on the human body. In this presentation, I will demonstrate a wearable multichannel patch that can sense a collection of signals from the human skin in a wireless mode.