EVENT DETAILS
Please join the Chemical and Biological Engineering Department for student seminars by Heather Calcaterra and Yuanwei Li.
Heather Calcaterra will present a seminar titled "Shape Memory in Self Adapting Colloidal Crystals."
ABSTRACT: Mechanically responsive crystals, which exhibit reversible, rapid, and complex dynamics, are essential to the development flexible electronics, artificial muscles, and various dynamic components in soft robotics. Due to the limited flexibility of the atomic bonds making up the crystals, to date, only a limited number of deformation modes can be obtained in mechanically responsive crystals. To address this limitation, we report the reversible mechanical responsiveness of colloidal crystals engineered with DNA bonds to deformations typically considered irrecoverable in conventional molecular and atomic crystals. These advances were obtained through the synthesis of large (>50 um) single crystals, which enable previously unrealizable characterization techniques including in-situ optical microscopy and single-crystal x-ray diffraction, as well as subsequent study of their state-switchable optical properties. This work sheds light into both the unprecedented nature of the macroscale deformation and recovery as well as the flexible and resilient internal structure of DNA-engineered crystals.
Yuanwei Li will present a seminar titled "Open-channel Colloidal Superlattices."
ABSTRACT: Although tremendous advances have been made in preparing porous crystals from molecular precursors, there are no general ways of designing and making topologically diversified porous colloidal crystals over the 10-1,000?nm length scale. Control over porosity in this size range would enable the tailoring of molecular absorption and storage, separation, chemical sensing, catalytic, optical, and mechanical properties of such materials. Here, a universal approach for synthesizing metallic open-channel superlattices with pores of 10 to 1,000?nm from DNA-modified hollow colloidal nanoparticles (NPs) is reported. By tuning hollow NP geometry and DNA design, one can adjust crystal pore geometry (pore size and shape) and channel topology (the way in which pores are interconnected). The assembly of hollow NPs is driven by edge-to-edge rather than face-to-face DNA-DNA interactions. Two new design rules describing this assembly regime emerge from these studies and are then used to synthesize 12 open-channel superlattices with control over crystal symmetry, channel geometry and topology. The open channels can be selectively occupied by guests of the appropriate size and that are modified with complementary DNA (for example, Au NPs). These open-channel colloidal superlattices not only have the potential to exhibit unnatural optical and mechanical properties that make them attractive as optical and mechanical metamaterials, but also can be useful for localizing large guests for a variety of applications.
Bagels and coffee will be provided at 11am, and the seminar will start at 11:10am. Please plan to arrive on time to grab a bagel and mingle!
TIME Thursday February 23, 2023 at 11:00 AM - 12:00 PM
LOCATION L361, Technological Institute map it
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CONTACT Baylee Byers baylee.byers@northwestern.edu
CALENDAR McCormick-Chemical and Biological Engineering (ChBE)