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The copolymerization of chlorotrifluoroethylene (CTFE) with several vinyl ethers (VE) (hydroxyethyl vinyl ether, glycidyl vinyl ether, and chloroethyl vinyl ether) was studied. CTFE is an acceptor monomer (e -+2), whereas the VE's are highly donor ones (e --2), so they can copolymerize and lead to alternating copolymers. Such a behavior was shown by determining the composition of the copolymer at the beginning of the reaction, and we proved by I9F NMR of CTFE that the equilibrium constant of the chargetransfer complex formation (CTC) is high ( K = 1.4). Then, the structure of the copolymer was investigated by performing the cotelomerization of CTFE and a VE with a fluorinated thiol ( C G F~~C~H~S H ) .This reaction produced both the monoadducts and the dimer structure (opposite to that expected from the CTC) which are in contradiction with the polymerization by propagation of the transfer complex. Thus a polymerization of free monomers is proposed, and the alternating behavior of the copolymer comes from the great difference in polarity between these two kinds of monomers.

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The construction of “smart” materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces and smart nanomaterials. Structural flexibility of these materials is known to be conferred by weak intermolecular forces involved in self-assembly strategies. However, some fundamental mechanisms responsible for conformational lability remain unexplored. Furthermore, the role played by stronger bonds, such as coordination, ionic and covalent bonding, is sometimes neglected while they can be employed readily to produce mechanically robust but also chemically reversible structures. In this review, recent applications of structural flexibility and molecular motions in self-assembled nanostructures are discussed. Special focus is given to advanced materials exhibiting significant performance changes after an external stimulus is applied, such as light exposure, pH variation, heat treatment or electromagnetic field. The crucial role played by strong intra- and weak intermolecular interactions on structural lability and responsiveness is highlighted.

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