[Crib-list] SPEAKER: Jerry Wang (MIT) | CRIBB Seminar | Friday, Dec. 2, 2016 | TIME: 1:00 PM - 2:00 PM | Building 32, Room 141 (Stata)

[daisymae@mit.edu]

 	COMPUTATIONAL RESEARCH in BOSTON and BEYOND SEMINAR


DATE:		FRIDAY, DECEMBER 2, 2016
TIME:		1:00 PM - 2:00 PM
LOCATION:	Building 32, Room 141  (STATA)
 		 (32 Vassar Street, Cambridge)

 		 Pizza and beverages will be provided at 12:45 PM
 		 outside Room 141.


TITLE:		Computational Modeling of Nanoconfined Fluids:
 		 Big Surprises Come in (Very) Small Packages


SPEAKER:	JERRY WANG  (Massachusetts Institute of Technology)


ABSTRACT:

Nanoscale fluids, unlike their macroscale cousins, exhibit a number of 
surprising effects that are not present within continuum theories. In 
particular, the equilibrium and transport properties of nanoconfined fluids can 
be substantially different from the bulk properties of that fluid. 
Understanding the physical basis for these anomalous fluid properties including 
nanoconfined fluid structure, density, and self-diffusivity is central to many 
pursuits in nanoscale technology. These nanofluidic phenomena afford great 
opportunities to think big by thinking small specific engineering applications 
include nanoporous water filters to nanoscale drug delivery mechanisms to 
nanoscale heat transfer devices (as well as high-efficiency molecular 
simulation methods, for those of us who identify as computational engineers)!

In this talk, we present a theoretical and computational description of these 
phenomena in the context of dense simple fluids confined within a variety of 
nanoscale structures, including carbon nanotubes and graphene nanoslits. We 
show that the anomalous nanoconfined fluid density can be substantially lower 
than the bulk density, and that this reduced density is primarily due to 
repulsive fluid-solid interactions. Using a mean-field approach, we obtain 
closed-form analytical results for the length-scales associated with fluid 
layering near the solid-fluid interface. These results allow us to predict the 
equilibrium fluid density as a function of the confinement length-scale. Our 
predictions are in excellent agreement with molecular dynamics simulations as 
well as results from the experimental literature.

We also show that the fluid-solid energy landscape and associated density 
profile can be used to explain the anomalous diffusive transport observed in 
such systems. In particular, the presence of a layered structure near the 
fluid-solid interface implies that fluid molecules near the solid wall exhibit 
different dynamics as compared to bulk fluid molecules. By constructing 
different models for diffusion in the near-wall and the bulk regions of the 
CNT, we show that we can approximately predict the overall diffusive behavior 
of the nanoconfined fluid. We demonstrate that these results are in agreement 
with molecular dynamics simulations.  We show how several aspects of this 
theory can be used to model more-complex fluids, including water.  Finally, we 
demonstrate how accurate knowledge of these anomalous fluid properties can 
inform simple models of nanoscale mass and heat transfer phenomena.

==========================================

Massachusetts Institute of Technology
Cambridge, MA


For information about the COMPUTATIONAL RESEARCH in BOSTON and BEYOND Seminar, 
please visit...


 			http://math.mit.edu/crib/



===
Shirley A. Entzminger
Administrative Assistant II
Department of Mathematics
Massachusetts Institute of Technology
77 Massachusetts Avenue
Building 2, Room 350A
Cambridge, MA 02139
PHONE:	(617) 253-4347
FAX:	(617) 253-4358
E-mail:	daisymae at math.mit.edu
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