Engineered Molecular Fluidics NSF NIRT Grant 0609087 PIs: S.S. Sheiko1, K. Matyjaszewski2, M. Rubins

1
Engineered Molecular FluidicsNSF NIRT Grant
0609087PIs S.S. Sheiko1, K. Matyjaszewski2, M.
Rubinstein1, O. Velev31University of North
Carolina at Chapel Hill, 2Carnegie Mellon
University, 3North Carolina State University
Constrained spreading of a molecular brush
Concept and methodology
Katya Zhulina and Gregory Randall
As alternative to (a) closed-channel systems, we
study (b) open structures, where monolayer
masses, residing on a substrate, are moved and
configured by an external force.
m gt NS1/2 un-stretched molecule (same as
spreading of linear chain)
NS lt m lt NS1/2 stretched backbone, un-stretched
side chains
(NS)1/3 lt m lt NS stretched backbone and side
chains
S-1/4 lt m lt (NS)1/3 fully stretched backbone
and H S-1/2
m lt S-1/4 saturated lower layer and appearance
of the cap
Fbb/(mkT)
Tension energy per backbone monomer
NS7/4
NS/m3
Free energy per side chain _at_ constant volume
HhLNb3
(NS/m)1/2/m
1
NS/m2
1/(NS)
1/N
spreading
disjoining
backbone stretching
side chain stretching

• Advantages
• smaller volume and direct accessibility
• dynamically configurable flow control
• rapid heat exchange
• substrate-mediated mixing, orientation, and
  shape of macromolecules

m
NS1/2
NS
(NS)1/3
S-1/4
Molecular conformation within 2-D asymmetric
mixtures
Andrey Dobrynin and Frank Sun
Phys. Rev. Lett. 99, 137801 (2007)
Electric field manipulation of thin films
Flow-induced molecular fractionation
Jairus Kleinert, Sejong Kim
Mike Barrett, Frank Sun, and David Shirvaniants
Thin wetting film spreading by electro-osmosis
heterogeneous substrates
5.7 x 104 µm2/ Vsec
µeof standard electroosmotic mobility e
permittivity (80)(8.85 10-12 F/m) ? zeta
potential of mica - 80 mV ? viscosity
9x10-4 Pasec
Manipulating of molecular fluorophore in a thin
film
Time