Fabrication of Highly Ordered Polymeric Nanodot and Nanowire Arrays Templated by Supramolecular Assembly Block Copolymer Nanoporous Thin Films
Xikui Liu
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Manfred Stamm
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X. Liu College of Polymer Science and Engineering, Sichuan University
, Sichuan 610065,
China
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X. Liu (&) M. Stamm (&) Department of Nanostructured Materials, Leibniz Institute of Polymer Research Dresden
, Hohe Str. 6,
01069 Dresden, Germany
Realizing the vast technological potential of patternable block copolymers requires both the precise controlling of the orientation and long-range ordering, which is still a challenging topic so far. Recently, we have demonstrated that ordered nanoporous thin film can be fabricated from a simple supramolecular assembly approach. Here we will extend this approach and provide a general route to fabricate large areas of highly ordered polymeric nanodot and nanowire arrays. We revealed that under a mixture solvent annealing atmosphere, a neardefect-free nanoporous thin film over large areas can be achieved. Under the direction of interpolymer hydrogen bonding and capillary action of nanopores, this ordered porous nanotemplate can be properly filled with phenolic resin precursor, followed by curation and pyrolysis at middle temperature to remove the nanotemplate, a perfect ordered polymer nanodot arrays replication was obtained. The orientation of the supramolecular assembly thin films can be readily re-aligned parallel to the substrate upon exposure to chloroform vapor, so this facile nanotemplate replica method can be further extend to generate large areas of polymeric nanowire arrays. Thus, we achieved a successful sub-30 nm patterns nanotemplates transfer methodology for fabricating polymeric nanopattern arrays with highly ordered structure and tunable morphologies.
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Precise fabrication of large areas of ordered nanoscale
structures is essential for microelectronic and information
technology, the broad scope of top-down processes,
including conventional immersion lithography, extreme
ultraviolet lithography, and soft lithography have been
proposed to meet the demands of devices miniaturization,
these endeavors have enabled the lateral dimensions of
devices to be readily shrunk below 100 nm [13].
However, as the lateral dimension goes smaller and smaller,
these top-down approaches become extremely difficult
and expensive, hence, other methodologies of creating
nanostructures are of great interesting if they can offer
advantages in reduced production cost, smaller feature
sizes, and more complex nanopatterns. Nanofabrication via
block copolymer self assembly represents one of the most
powerful candidates, and is now taking as the most
promising methodology for next-generation lithography
[46], mainly due to their intrinsic nanoscale dimensions,
facile synthesis, and strict control of architecture. Ever
since the self assembly of block copolymers was
introduced as a powerful bottom-up route to well-organized
nanostructures decade ago, many efforts have been
devoted: as through chemical modification of the block
copolymer structure to achieve special functionalities,
exploring electric fields, and interfacial interactions to
control the orientation, and utilizing solvent induced
ordering, salt complexes, and shear fields to achieve ordered
arrays [710]. Among which solvent annealing is of
particularly beneficial mainly due to their mild process
condition and no need for additional complicated apparatus,
and now it has turn out to be a very simple while robust
approach to generate almost defect-free microphase
separation structures in BCP thin films [1113]. Even more, it
appears to be the single possible way for thermal lible
systems such supramolecular block copolymers based on
noncovalently bonding. Further research revealed the use of
a co-solvent atmosphere, will enables one to enhancing the
ordering process ever further [14, 15]. However, a critical
drawback of solvent annealing is that BCP thin film often
de-wets its substrate during solvent exposure as have been
already pointed out by several researchers [1619]. This
makes it is very difficult to obtain uniform and ordered BCP
thin film over a macroscopic area without the direction of
additional external fields. In many cases, realizing the vast
technological potential of block copolymers requires both
the precise controlling of the orientation and long-range
ordering, however, weakness still remains, so far, only few
works have reported to achieve highly ordered thin film
nanotemplates, and the control of well-organized structures
over large scale is still a challenging topic.
In recent decade, Ikkala and ten Brinke have thoroughly
demonstrated that well-ordered nanostructures in the bulk
may be fabricated through supramolecular assemblies
(SMA) of low molecular amphiphiles and block
copolymers [20, 21]. The amphiphiles can be physically bonded
to homopolymers and block copolymers using noncovalent
interactions, this complexation can lead to the formation of
supramolcecular block copolymer which can further
assembled into hierarchy nanostructures with various
responsive prope (...truncated)