metal–ligand interactions and/or the breakage of (ionic) clusters (see Fig. 9).
Subsequently, this change leads to healing of the mechanical damage. The original
functionality is restored after reformation of complexes and/or clusters
(i.e., immobilization). Note that the original structure is not restored, but that a
new molecular pattern is created. The phenomena of reversibility and switchability
are well known from metal–ligand bonds in solution, but the study of the behavior
of the metal–ligand interaction in the solid state is difficult [102–105]. New
methods have to be developed in order to investigate these interesting materials
in more detail.
5 Conclusion and Outlook
The fascinating material class of metallopolymers combines the world of covalent
polymers pioneered by Staudinger with the concepts and systems of supramolecular
chemistry and shows interesting properties due to the marriage of polymeric features
with the distinct properties of metal complexes. The combination of a wide range of
different metal ions with the corresponding ligands allows tuning of the desired
properties. In the field of stimuli-responsive polymers, metallopolymers have been
frequently applied. Their switchable properties enable the utilization of interesting
triggers (e.g., light) for a self-healing process. However, in contrast to other
noncovalent interactions (particularly in comparison to the prime example, hydrogen
bonds), metal complexes have been applied less frequently in self-healing materials.
First examples confirm the great potential of these materials and significant improvements can be expected in the coming years in this field. Nature, which successfully
utilizes noncovalent interactions (e.g., in mussel byssus threads), reveals another
important issue: the order and spatial arrangement of the metal complexes.
The healing of some synthetic materials has been described on the molecular as
well as macroscopic level in recent years.
Metallopolymers, as one of the youngest members of the self-healing polymer
family, are a rather new research field. Many possibilities for the design of selfhealing polymers are imaginable. Moreover, further intense research is required to
clarify the detailed mechanisms of the healing within these materials. A deeper
understanding of the behavior of the metal–ligand bonds in the solid state is
required. This knowledge can only be gained with the use of new characterization
techniques that can reveal the molecular processes within polymeric materials. The
utilization of self-healing metallopolymers for potential applications will be the
main focus of future research. Due to their fascinating properties (e.g., light
absorption or emission), metallopolymers offer the possibility to design new functional coatings [9, 106–109]. For this purpose, the combination of optical and selfhealing properties is necessary. This combination could result in a new class of
functional coatings. In that context, an improved processability of the self-healing
metallopolymer is required and known methods must be applied for these materials
[9, 110–112].
Metallopolymers as an Emerging Class of Self-Healing Materials
251
Subsequently, this change leads to healing of the mechanical damage. The original
functionality is restored after reformation of complexes and/or clusters
(i.e., immobilization). Note that the original structure is not restored, but that a
new molecular pattern is created. The phenomena of reversibility and switchability
are well known from metal–ligand bonds in solution, but the study of the behavior
of the metal–ligand interaction in the solid state is difficult [102–105]. New
methods have to be developed in order to investigate these interesting materials
in more detail.
5 Conclusion and Outlook
The fascinating material class of metallopolymers combines the world of covalent
polymers pioneered by Staudinger with the concepts and systems of supramolecular
chemistry and shows interesting properties due to the marriage of polymeric features
with the distinct properties of metal complexes. The combination of a wide range of
different metal ions with the corresponding ligands allows tuning of the desired
properties. In the field of stimuli-responsive polymers, metallopolymers have been
frequently applied. Their switchable properties enable the utilization of interesting
triggers (e.g., light) for a self-healing process. However, in contrast to other
noncovalent interactions (particularly in comparison to the prime example, hydrogen
bonds), metal complexes have been applied less frequently in self-healing materials.
First examples confirm the great potential of these materials and significant improvements can be expected in the coming years in this field. Nature, which successfully
utilizes noncovalent interactions (e.g., in mussel byssus threads), reveals another
important issue: the order and spatial arrangement of the metal complexes.
The healing of some synthetic materials has been described on the molecular as
well as macroscopic level in recent years.
Metallopolymers, as one of the youngest members of the self-healing polymer
family, are a rather new research field. Many possibilities for the design of selfhealing polymers are imaginable. Moreover, further intense research is required to
clarify the detailed mechanisms of the healing within these materials. A deeper
understanding of the behavior of the metal–ligand bonds in the solid state is
required. This knowledge can only be gained with the use of new characterization
techniques that can reveal the molecular processes within polymeric materials. The
utilization of self-healing metallopolymers for potential applications will be the
main focus of future research. Due to their fascinating properties (e.g., light
absorption or emission), metallopolymers offer the possibility to design new functional coatings [9, 106–109]. For this purpose, the combination of optical and selfhealing properties is necessary. This combination could result in a new class of
functional coatings. In that context, an improved processability of the self-healing
metallopolymer is required and known methods must be applied for these materials
[9, 110–112].
Metallopolymers as an Emerging Class of Self-Healing Materials
251