Title: Surface Water-Driven Engineering of Cellulose Fibers
Date and Time: Friday, November 10. Refreshments served at 12:50 p.m. Seminar starts at 1 p.m.
Location: CHBE 102 (2360 East Mall)
Cellulose and its derivatives form a complex array of tunable materials. Beyond the molecular level, however, the chemistry becomes complex due to the extent of scales one can define the basis unit. Cellulose nanofibers and pulp for example are orders of magnitude different from each other. Herein, we show how surface chemistry offers a good window to this complexity. We demonstrate that physisorbed water plays a much larger role in surface chemistry, hence use of these ubiquitous materials. First, we discuss the droplet size-dependent chimera amphiphilicity driven by our ability to exploit water as a comonomer. We exploit this behavior to create dynamic/tunable 4D microfluidic paper-based devices that are further automated using embedded magnetic switching for use in lab-on-paper point of use devices. Given the porosity profile of a paper, asymmetric calendaring with concomitant surface modification implies that such microfluidic devices can be prepared with a regular ball pen. Given the amphiphilicity, it is obvious that these materials are lubricious as demonstrated by their use as solid lubricants albeit with a need to tune fibers aspect ratio. We further demonstrate that this water-based chemistry is amicable to control of flame propagation on such modified materials in situ switching combustion to pyrolysis. The switch to pyrolysis leads to the formation of graphitic carbon nano- to micro- tubes, albeit with porous walls. These tubes can further be elaborated into tunable bandgap materials with a wide range of potential applications. In summary, we exploit a mischaracterization in surface reactions on cellulose (and by extension other materials) to create an array of devices and demonstrate unique uses of cellulose fibers from CNF to pulp and paper.
MARTIN THUO is a Professor in the Department of materials science & engineering at NCSU. He was the Schafer 2050 professor at Iowa state University in the Department of materials science & engineering and in electrical and computer engineering. Prior to this, he was a Mary-Fieser (2009-2011) and NSEC (2011-2013) Fellow at Harvard University under Prof. George M. Whitesides. He is the recipient of several awards like the ACS nano rising star, Akinc excellence in research award, Lynn-Anderson research excellence award, Black & Veatch faculty fellowship, among others. His research work has resulted in >40 patent disclosures and several startup companies. He is a co-host of the ICAN-X talks and serves on the boards of various journals. His research interests encompass the general theme of frugal innovation through simplicity and surface thermodynamics.