Nature provides wonderful inspiration and thus may guide the way in many
technological areas, but biological processes at the molecular level are often highly
complex and thus cannot provide the answer to all technological challenges, at
least not in the foreseeable future. Compared to biological macromolecules,
the information content of synthetic macromolecules is often still relatively low.
Yet even with only two, three, or four monomers along the synthetic chain, the
emerging structural diversity is already quite substantial. Block copolymers (BCP)
with two or three (or more) monomers blocked along the chain provide a model
polymer architecture for looking at this diversity. While in a very rudimentary
way mimicking the complexity of blocked protein primary sequences, BCP selfassembly (SA) can still be understood quantitatively and thus provides a wonderful
toolbox for studying the processes of structure formation. Furthermore, as will
become apparent from this article, more and more potential applications are emerging
in which not only the scalar properties of block copolymers are used, but also in
which the block sequence-directed SA structure plays an important direct role. It is to
this area of BCP SA that the Wiesner group at Cornell University has devoted much
effort to pushing the limits of our understanding of polymer science. In this review,
we summarize past achievements of BCP hybrid SA studies, with emphasis on the
results of the Wiesner group on such materials, and share our blueprints for the
frontiers of polymer research in this particular field of polymer science.
Modern science and technology often seeks “smart” functional materials for
today’s applications, combining novel functionalities with solution-based processablity, which is usually difficult to obtain from only one type of organic or inorganic
material. Much effort has therefore been paid to the synthesis of hybrid materials that
combine advantageous features of both organics and inorganics [4]. The Wiesner
group has utilized BCP SA to direct the structure of inorganic materials. In order to
minimize their free energy, BCPs self-assemble into periodically ordered structures at
the nanoscale. Due to the ease of tuning aspects of the chemical structure of BCPs
such as chain length and composition, BCPs are of great use in designing such
nanostructures from the bottom up. However, BCPs that readily self-assemble into
such structures typically lack a variety of desired functionalities, including magnetic
or electric properties. Exploiting the power of structural design from BCPs one can
use their SA to direct the structure of functional inorganic materials into ordered
nanostructures, thereby combining the best of both worlds. Furthermore, BCP SA is a
bottom-up type of synthetic approach that is scalable and solution based, and thus
relatively cost-effective. It is thus a powerful tool, offering a facile route to synthesis
of novel materials that should also be relevant to industrial applications.
This review summarizes more than a decade of research efforts on BCP-derived
hybrid materials by the Wiesner group and others. Section 2 provides a brief
introduction of BCP SA, serving as background knowledge to unfamiliar readers.
The following sections include descriptions of BCP-derived structures (Sect. 3),
synthetic methods (Sect. 4), different material classes structure-directed by BCPs
(Sect. 5), and potential application areas (Sect. 6). SA structures are important
ingredients that BCP scientists can exploit to design novel materials. A variety of
the synthetic methods are summarized, encompassing hybrids with thermodynamic
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K. Hur and U. Wiesner
technological areas, but biological processes at the molecular level are often highly
complex and thus cannot provide the answer to all technological challenges, at
least not in the foreseeable future. Compared to biological macromolecules,
the information content of synthetic macromolecules is often still relatively low.
Yet even with only two, three, or four monomers along the synthetic chain, the
emerging structural diversity is already quite substantial. Block copolymers (BCP)
with two or three (or more) monomers blocked along the chain provide a model
polymer architecture for looking at this diversity. While in a very rudimentary
way mimicking the complexity of blocked protein primary sequences, BCP selfassembly (SA) can still be understood quantitatively and thus provides a wonderful
toolbox for studying the processes of structure formation. Furthermore, as will
become apparent from this article, more and more potential applications are emerging
in which not only the scalar properties of block copolymers are used, but also in
which the block sequence-directed SA structure plays an important direct role. It is to
this area of BCP SA that the Wiesner group at Cornell University has devoted much
effort to pushing the limits of our understanding of polymer science. In this review,
we summarize past achievements of BCP hybrid SA studies, with emphasis on the
results of the Wiesner group on such materials, and share our blueprints for the
frontiers of polymer research in this particular field of polymer science.
Modern science and technology often seeks “smart” functional materials for
today’s applications, combining novel functionalities with solution-based processablity, which is usually difficult to obtain from only one type of organic or inorganic
material. Much effort has therefore been paid to the synthesis of hybrid materials that
combine advantageous features of both organics and inorganics [4]. The Wiesner
group has utilized BCP SA to direct the structure of inorganic materials. In order to
minimize their free energy, BCPs self-assemble into periodically ordered structures at
the nanoscale. Due to the ease of tuning aspects of the chemical structure of BCPs
such as chain length and composition, BCPs are of great use in designing such
nanostructures from the bottom up. However, BCPs that readily self-assemble into
such structures typically lack a variety of desired functionalities, including magnetic
or electric properties. Exploiting the power of structural design from BCPs one can
use their SA to direct the structure of functional inorganic materials into ordered
nanostructures, thereby combining the best of both worlds. Furthermore, BCP SA is a
bottom-up type of synthetic approach that is scalable and solution based, and thus
relatively cost-effective. It is thus a powerful tool, offering a facile route to synthesis
of novel materials that should also be relevant to industrial applications.
This review summarizes more than a decade of research efforts on BCP-derived
hybrid materials by the Wiesner group and others. Section 2 provides a brief
introduction of BCP SA, serving as background knowledge to unfamiliar readers.
The following sections include descriptions of BCP-derived structures (Sect. 3),
synthetic methods (Sect. 4), different material classes structure-directed by BCPs
(Sect. 5), and potential application areas (Sect. 6). SA structures are important
ingredients that BCP scientists can exploit to design novel materials. A variety of
the synthetic methods are summarized, encompassing hybrids with thermodynamic
262
K. Hur and U. Wiesner