Double Dynamic Supramolecular Polymers of Covalent Oligo- Dynamers Gaë l Schaeffer, † Eric Buhler, ‡ Sauveur J. Candau, † and Jean-Marie Lehn* ,† † Laboratoire de Chimie Supramole ́ culaire, Institut de Science et d’Inge ́ nierie Supramole ́ culaires (ISIS), Universite ́ de Strasbourg, 8 allé e Gaspard Monge, Strasbourg 67000, France ‡ Laboratoire Matie ̀ re et Systè mes Complexes (MSC) UMR 7057, Universite ́ Paris Diderot-Paris 7, Bâ timent Condorcet, 75205 Paris cedex 13, France * S Supporting Information ABSTRACT: Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (“double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in which the monomers are connected by reversible covalent interactions and (2) the association of these oligomers through supramolecular interactions (hydrogen bonding). This procedure leads to the formation of an entity that can be seen as a supramolecular polymer of molecular oligo-dynamers. It thus combines two types of dynamic processes that do not simply alternate in the polymeric chain but may be incorporated in various ratios. These non-alternating double dynamic polymers have been generated by sequential construction and the different steps have been characterized by NMR spectroscopy, mass spectrometry and light scattering. ■ INTRODUCTION The use of dynamic connections between monomers leads to the generation of dynamic polymers, termed, in short, dynamers. 1-16 These entities exhibit reversible formation and component exchange due to the lability of the connections in the polymeric chain. They present the ability to undergo modification of their constitution via incorporation/decorpora- tion and exchange of components as well as the capability to adapt their length in response to a specific stimulus or to changes in the environment. A range of novel properties, including self-healing 17-20 may be expected to become accessible. The dynamic character may result from the use of either supramolecular or molecular (reversible covalent) junctions between the monomers. Several types of noncovalent interactions, such as hydrogen bonds, 19,21-31 metal-ligand interactions 32-36 or other types of “weak interactions” 37-46 have been used to generate supramolecular polymers. 47 Similarly, reversible covalent polymers have been created by using various reactions, such as transesterification, 48-51 trans- etherification, 52 Diels-Alder reactions, 20,53,54 boronate ester formation 55 or imine-like condensations. 3-13,56-62 Diversity and complexity in dynamers may be provided through the use of multiple dynamic processes in the main chain of a polymer. 63 It gives access to entities that display potentially the properties of all the functional groups used in the polymer and thus are responsive to a larger number of stimuli. It has been achieved by combining supramolecular and molecular dynamicities to form a polymer. Such dynamers have been obtained with, for example, hydrogen bonds and acylhydrazone units in the main chain (double dynamer), 64 where the two dynamic functions can be addressed selectively. Other examples have shown that it is possible to prepare a supramolecular polymer by using two different types of noncovalent interactions, such as hydrogen bonds and metal ion coordination, 65-68 which can also be used to control the sequence in a block copolymer. 69 More recently, the orthogonality of these two types of interactions has been demonstrated in dendritic systems. 70 Different combinations of dynamic functions have also been implemented to form dynamers. A system combining hydrogen bonds and electro- static interactions has been developed, showing that these two types of interactions can be used simultaneously. 71,72 Coulombic interactions have also been combined with coordination chemistry to create multiply stranded polymeric entities. 73 Host-guest interactions have been utilized together with metal-ligand interactions to yield linear 74 or cross-linked polymers. 75 Similarly, the formation of polymeric chains has been achieved by combining hydrogen bonding with host- guest 76 or with pi-stacking interactions. 77,78 Supra-macro- molecular species have also been obtained by using two different types of similar dynamic functions, e.g., two types of hydrogen bonding units 79,80 (in some cases, geometrically orthogonal) or two di fferent metal-ligand coordination interactions. 81 More recently, two dynamic functions have Received: March 1, 2013 Revised: June 13, 2013 Published: July 1, 2013 Article pubs.acs.org/Macromolecules © 2013 American Chemical Society 5664 dx.doi.org/10.1021/ma400449u | Macromolecules 2013, 46, 5664-5671