Prof. Guoliang (Greg) Liu
Dept. of Chemistry
Thursday, February 28, 2019 - 2:00pm
MRL Room 2053
Prof. Chris Bates
First, I will describe the synthesis of a new type of porous carbon fibers from block copolymers. Carbon fibers possess high surface areas and rich functionalities for interacting with ions, molecules, and particles. However, the control over their porosity has remained challenging. Conventional syntheses rely on blending polyacrylonitrile with sacrificial additives, which macrophase-separate and result in poorly-controlled pores. Here we use the microphase-separation of block copolymers to synthesize porous carbon fibers (PCFs) with well-controlled mesopores and micropores. Without infiltrating any precursors or dopants, block copolymers are directly converted to nitrogen and oxygen dual-doped PCFs. Owing to the optimized bimodal pores and interconnected porous network, the block copolymer-based porous carbon fibers exhibit outstanding ion transport properties and ultrahigh capacitances in supercapacitors. The use of block copolymer precursors revolutionizes the synthesis of PCFs. The advanced electrochemical properties signify that PCFs represent a new platform material for electrochemical energy storage.
Second, I will present the design of plasmonic polymer nanocomposites for tinted glass. The state-of-the-art commercial tinted glass is coated with a full layer of metalized film to decrease the transmittance of electromagnetic waves. Besides the high cost of the metal layer, the key limitation of such light-reflecting glass is the lack of spectral selectivity. To date, there has been no demonstration of stable and spectral-selective glass that covers the entire visible and near-infrared (NIR). To address the challenge, here by judiciously controlling the planar orientation of 2D plasmonic silver nanoplates (AgNPs) in polymer nanocomposites, we effectively harness the transmittance, reflectance, and filtration of any wavelength across the visible and NIR. In contrast to the conventional bulk polymer nanocomposites where plasmonic nanoparticles are randomly mixed within the polymers, our thin-film polymer nanocomposites employ a minimal amount of planarly oriented metal nanoparticles and yet efficiently manage light across the visible and NIR. The thin-film polymer nanocomposites are expected to impact on spectral-selective tinted glass, as well as on sensing, optics, optoelectronics, and photonics.