materials displaying multiple control adaptive behavior. Significantly, the process
presents strong component selection driven by medium/hydrophobic effects. The
process generates the dynamer that incorporates the monomer possessing the largest
hydrophobic area into the compact rod-like nanostructure so as to minimize contacts
between hydrophobic residues and water [110] (see also figure 13 in [42]).
The constitutional plasticity of constitutional dynamic materials endows them
with tunability and responsiveness to stimuli, as for instance in the transport
features of dynamic polymer membranes [111], in the stimuli-responsiveness of
supramolecular polymeric materials [112], and in the design of adaptable functional
materials and devices [113–115].
5 Adaptive Polymer Networks Towards a Systems
Materials/Polymer Science
The behavior of adaptive chemical systems can be conceptualized in terms of
adaptive networks. Such a representation also applies to adaptive materials, and
in particular to dynamic polymers. I shall recall here some points made earlier [41,
43, 116] and present some additional aspects that will be expanded in more detail on
another occasion.
The sets of dynamically interconverting constituents generated by CDC that are
connected structurally (molecular and supramolecular arrays) and eventually also
through reaction (sets of connected reactions) define constitutional dynamic networks (CDNs). These CDNs may couple to either reversible or irreversible thermodynamic processes and present a specific stability or robustness with respect to
external perturbations. The constituents present agonistic and antagonistic relationships depending on whether the increased expression of a given constituent
decreases or increases one or more of the others. Thus, feedback between the linked
species leads to simultaneous upregulation/amplification or downregulation of the
different constituents depending on the type of connection.
CDNs may be represented by weighted graphs, in which vertices, edges, and
diagonals represent the connections between the members of a set, their agonistic or
antagonistic relationships, as well as their relative weights. The simplest case is that
of four constituents, AB, AB
0 , A
0 B, and A
0 B
0 , located at the corners of a square and
generated from four components A, A
0 , B, and B
0 by reversible connection of A, A
0
with B, B
0 . If, for example, subjecting such a system to the action of a physical
stimulus or to the interaction with a chemical effector, E, drives the upregulation of
AB, it will simultaneously amplify its agonist A
0 B
0 and downregulate its antagonists
AB
0 and A
0 B, with which it shares a component (see also figure 14 in [116]). Thus,
CDNs are adaptive, responding to the action of various factors by a change in the
weight or fraction of the different linked constituents, and may be termed adaptive
constitutional networks (ACNs).
166
J.-M. Lehn
presents strong component selection driven by medium/hydrophobic effects. The
process generates the dynamer that incorporates the monomer possessing the largest
hydrophobic area into the compact rod-like nanostructure so as to minimize contacts
between hydrophobic residues and water [110] (see also figure 13 in [42]).
The constitutional plasticity of constitutional dynamic materials endows them
with tunability and responsiveness to stimuli, as for instance in the transport
features of dynamic polymer membranes [111], in the stimuli-responsiveness of
supramolecular polymeric materials [112], and in the design of adaptable functional
materials and devices [113–115].
5 Adaptive Polymer Networks Towards a Systems
Materials/Polymer Science
The behavior of adaptive chemical systems can be conceptualized in terms of
adaptive networks. Such a representation also applies to adaptive materials, and
in particular to dynamic polymers. I shall recall here some points made earlier [41,
43, 116] and present some additional aspects that will be expanded in more detail on
another occasion.
The sets of dynamically interconverting constituents generated by CDC that are
connected structurally (molecular and supramolecular arrays) and eventually also
through reaction (sets of connected reactions) define constitutional dynamic networks (CDNs). These CDNs may couple to either reversible or irreversible thermodynamic processes and present a specific stability or robustness with respect to
external perturbations. The constituents present agonistic and antagonistic relationships depending on whether the increased expression of a given constituent
decreases or increases one or more of the others. Thus, feedback between the linked
species leads to simultaneous upregulation/amplification or downregulation of the
different constituents depending on the type of connection.
CDNs may be represented by weighted graphs, in which vertices, edges, and
diagonals represent the connections between the members of a set, their agonistic or
antagonistic relationships, as well as their relative weights. The simplest case is that
of four constituents, AB, AB
0 , A
0 B, and A
0 B
0 , located at the corners of a square and
generated from four components A, A
0 , B, and B
0 by reversible connection of A, A
0
with B, B
0 . If, for example, subjecting such a system to the action of a physical
stimulus or to the interaction with a chemical effector, E, drives the upregulation of
AB, it will simultaneously amplify its agonist A
0 B
0 and downregulate its antagonists
AB
0 and A
0 B, with which it shares a component (see also figure 14 in [116]). Thus,
CDNs are adaptive, responding to the action of various factors by a change in the
weight or fraction of the different linked constituents, and may be termed adaptive
constitutional networks (ACNs).
166
J.-M. Lehn