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.