Seminars

The MRSEC holds seminars presenting research at the frontier of Bioinspired Soft Materials. The seminars are targeted towards grad students and other researchers in the field, although everyone is invited to attend. As the topic is highly interdisciplinary, seminars are designed to be accessible to a wide range of backgrounds. 

The seminars take place in Abelson 229 at 4PM.

MRSEC Seminars Organizers:
John Berezney (Dogic/Fraden Lab Postdoc)

Thursday, September 19, 2019
Douglas Holmes, Boston University
Title: Functional Kirigami Mechanical Metamaterials for Actuators, Muscles, and Grippers
Abstract: It is far easier to bend an object than it is to stretch it, and so how does one design thin structures capable of stretching and adopting complex shapes? In recent years, scientists have used cuts in thin sheets to provide local regions that can easily deform. Termed kirigami, in reference to the ancient Japanese art of folding and cutting paper, kirigami-based mechanical metamaterials have provided a simple way to to endow a generic material with extraordinary properties. Lattice cuts, in which cuts are oriented perpendicular to the stretching direction, provide a simple way to enhance the stretchability of a thin sheet. We show that certain lattice configurations are more stretchable than others, while certain configurations produce an array of bistable unit cells. The bistability provides a means to tune the stiffness of the structure in situ, while also providing a means for mechanical memory. We demonstrate the how to switch between stable states using magnetic actuation. Lattice cuts on a curved sheets, i.e. kirigami shells, enable additional functionality. The natural curvature of the sheet causes the bistable lattices to curve together and close around an object, which enables the kirigami shells to act as soft robotic grippers. Finally, non-lattice cuts open up a range of actuation possibilities. Coupling these soft rotation modes with stiff lift modes enables us to generate kirigami linear actuators, that exhibit pitch, yaw, roll, and lift in response to uniaxial stretching. The underlying buckling mechanism is independent of thickness to a first order approximation, and thus these results translate down to 2D materials such as graphene and MoS2, as we demonstrate with MD simulations.
Abelson 229, 4PM

Thursday, September 26, 2019
Ashwin Gopinath, MIT
Title: DNA origami: The bridge to the bottom
Abstract: Conventional top-down nanofabrication, over the last six decades, has enabled almost all the complex electronic, optical and micro-fluidic devices that form the foundation of our society. Parallel efforts, exploring bottom-up self-assembly processes, have also enabled design and synthesis of structures like quantum dots, carbon nanotubes and unique bio-molecules that possess technologically relevant proper- ties unachievable top-down. While both these approaches have independently matured, ongoing efforts to create “hybrid nanostructures” combining both strategies, has been fraught with technical challenges. The main roadblock is the absence of a scalable method to deterministically organize components built bottom-up within top-down nanofabricated structures.
In this talk, I will first introduce a directed self-assembly technique that utilizes DNA origami as a molecular adaptor to modularly position, and orient, bottom-up nano-components (like quantum dots, light emitters and proteins) within top-down nanofabricated devices. I will then present experimental results demonstrating the utility of the technique to achieved absolute, arbitrarily scalable, control over the integration of discrete emitters inside optical devices. Finally, I conclude by presenting my vision of how a DNA origami based bridge between top-down and bottom-up nanofabrication can enable a range of highly transformative, and functional, devices. Specifically, I will present data demonstrating arrays of single-photon sources, method for extremely economical nanotexturing as well as a modular molecular interface between biology and solid-state.
Abelson 229, 4PM

Thursday, October 24, 2019
Ming Guo, MIT Mechanical Engineering
Abelson 229, 4PM

Thursday, November 7, 2019
Suraj Shankar, Harvard Society of Fellows
Abelson 229, 4PM

Thursday, November 14, 2019
Neel Joshi, Wyss Institute at Harvard University
Abelson 229, 4PM

Thursday, November 21, 2019
Prabhu Nott, Indian Institute of Science
Abelson 229, 4PM


 See past events.