 |
 |
Science at the Edge
Engineering Seminar
October
24th,
2014
11:30
a.m.
Room1400
Biomedical
and Physical Sciences Building
Refreshments
served
at 11:15 a.m.
Richard A.
Register
Department of Chemical and
Biological
Engineering
Princeton University,
Princeton, NJ
Block
Copolymer Thin
Films:
Structure,
Shear
Alignment, and Applications in Nanofabrication
Abstract
Block
copolymers have been
extensively studied for their ability to self-assemble into
microdomain
morphologies such as spheres, cylinders, and lamellae, with
typical
periodicities of 20-60 nm. Similar structures form when block
copolymers are
deposited as thin films on substrates; these films can serve
as excellent
templates for nanofabrication, where the block copolymer’s
nanodomain structure
is faithfully reproduced in an inorganic material—but the
final array of
inorganic objects is, at best, only as good as the structure
of the film from
which it was derived. Consequently,
we
have worked intensively to develop methods to manipulate the
structure of the
films. For example,
the polygrain
structure normally formed by these nanodomains can be
transformed to a
single-crystal texture, over macroscopic areas, by a simple
shearing
process. Shear can
also realign the domain
orientation locally in films with an otherwise macroscopic
orientation; create
complex orientation patterns on the millimeter scale; and even
transform
spheres into cylinders. We
have employed
these thin, substrate-supported block copolymer films to
fabricate dense arrays
of 20-40 nm metal or semiconductor particles:
dots (from sphere-forming block copolymers) or lines
(wires, from
cylinder-formers), all with a size and spacing set through
block copolymer molecular
weight. Such
shear-aligned thin-film
templates can also be stacked to produce square, rectangular,
or rhombic
grids. As a particular
example, we have
used this approach on shear-aligned films containing in-plane
cylinders to
fabricate centimeter-scale arrays of parallel nanowires; due
to their fine
pitch, such wire grids can polarize an exceptionally broad
range of wavelengths
extending down into the deep ultraviolet (for 193 nm
photolithography), with
90% or better efficiency.
Bio
Richard A. Register is Eugene Higgins
Professor and Chair of the
Department of Chemical and Biological Engineering at
Princeton University,
where he previously served as Director of the Princeton
Center for Complex
Materials, a broad-based Materials Research Science and
Engineering Center
funded by the National Science Foundation.
His research interests revolve around micro- and
nanostructured
polymers, such as block copolymers, polymer blends,
semicrystalline polymers,
and ionomers, ranging across their physics, synthesis,
characterization, and
applications. He was
named a Fellow of
the American Physical Society in 2001; received the Charles
M.A. Stine Award
from the American Institute of Chemical Engineers in 2002;
was honored with the
Graduate Mentoring Award from Princeton University in 2008;
and was named a
Fellow of the American Chemical Society in 2012.
For further
information
please contact Prof. Christina Chan, Department of Chemical
Engineering and
Materials Science at [log in to unmask]
Persons with disabilities have the right
to request and
receive reasonable accommodation. Please call the Department of
Chemical
Engineering and Materials Science at 355-5135 at least one day
prior to the
seminar; requests received after this date will be met when
possible.