Self-Assemblies, Folding, and Properties of Perylene Monomers, Oligomers, and Polymers - Molecular Self-Assembly: Advances and Applications - page 124

assembly to amplify the polymer population or translated into a
completely different polymer—protein. Furthermore, these proteins
as well as other biomolecules use exactly the same principle of self-
assembly to further organize into live cells. Again, cells communicate
to other cells using self-assembled complexes and are connected to
each other to form organs. Although nature ubiquitously uses the
self-assembly principle, chemists did not begin to explore molecular
self-assemblies until the late 20th century. Now, we are experiencing
an explosive growth about our understanding of molecular self-
assemblies.
In this chapter, we will review some of the fundamental forces
that drive molecular self-assemblies. The results of such forces
manifest both in intermolecular self-assemblies and intramolecular
self-assemblies. Intermolecular self-assemblies drive nanostructure
formation, whereas intramolecular assemblies result in folding of
the oligomers or polymers into nanostructures. In many systems,
concentration of the molecules drives the molecules into organized
assemblies. Therefore, a critical concentration can be defined, above
which significant phenomena associated with self-assemblies can be
observed. Next, we will exam the similarity and differences between
intermolecular self-assemblies (hereafter called self-assemblies)
and intramolecular self-assemblies (hereafter called folding). Taking
advantage of folding and unfolding, we will then outline the design of
DNA biosensors using hybrid polymers containing complementary
DNA blocks and chromophoric blocks.
Another significance of self-assemblies is their ability to direct
reaction pathways. The fact of self-assembling properties can be
understood as codes of recognizing self. Conversely, the fact that
other molecules do not participate in the assemblies manifests
specificity in molecular recognition. Such recognition can be further
exploited as molecular codes to control chemical reaction down the
desired pathway. Traditionally, chemical reactions are attributed to
functional groups; functional groups that are supposed to react but
did not react have no explanation. The molecular code concept adds
a new chapter in chemistry to advance our understanding regarding
chemical reactions. Under its guidance, functional groups that are
supposed to react and do not violate chemical codes are expected to
proceed along the favored reaction pathway. Even chiral molecular
codes can be designed and implemented to impart structure-
selective reactions.