Reprocessing and Recycling of Highly Cross-Linked Ion-Conducting Networks through Transalkylation Exchanges of C-N Bonds.

Exploiting exchangeable covalent bonds as dynamic cross-links recently afforded a new class of polymer materials coined as vitrimers. These permanent networks are insoluble and infusible, but the network topology can be reshuffled at high temperatures, thus enabling glasslike plastic deformation and reprocessing without depolymerization. We disclose herein the development of functional and high-value ion-conducting vitrimers that take inspiration from poly(ionic liquid)s. Tunable networks with high ionic content are obtained by the solvent- and catalyst-free polyaddition of an α-azide-ω-alkyne monomer and simultaneous alkylation of the resulting poly(1,2,3-triazole)s with a series of difunctional cross-linking agents. Temperature-induced transalkylation exchanges of C-N bonds between 1,2,3-triazolium cross-links and halide-functionalized dangling chains enable recycling and reprocessing of these highly cross-linked permanent networks. They can also be recycled by depolymerization with specific solvents able to displace the transalkylation equilibrium, and they display a great potential for applications that require solid electrolytes with excellent mechanical performances and facile processing such as supercapacitors, batteries, fuel cells, and separation membranes.

Accelerated solvent- and catalyst-free synthesis of 1,2,3-triazolium-based poly(ionic liquid)s.

A straightforward and expeditious monotopic approach for the preparation of 1,2,3-triazolium-based poly(ionic liquids) (TPILs) is reported. It is based on the solvent- and catalyst-free polyaddition of an α-azide-ω-alkyne monomer in the presence of methyl iodide or N-methyl bis[(trifluoromethyl)sulfonyl]imide alkylating agents. Poly(1,2,3-triazole)s generated in bulk or by thermal azide-alkyne cycloaddition (AAC) are quaternized in-situ to afford TPILs composed of 1,3,4- and 1,3,5-trisubstituted 1,2,3-triazolium units. The physical and ion-conducting properties of the prepared samples are compared with the TPILs composed solely of 1,3,4-trisubstituted 1,2,3-triazolium units obtained through a multistep approach involving copper(I)-catalyzed AAC polyaddition, quaternization of the 1,2,3-triazole groups, and anion metathesis. TPILs obtained through the monotopic approach display thermal stabilities and ionic conductivities comparable to their pure regioisomeric analogues.

Random heteropolymers preserve protein function in foreign environments.

The successful incorporation of active proteins into synthetic polymers could lead to a new class of materials with functions found only in living systems. However, proteins rarely function under the conditions suitable for polymer processing. On the basis of an analysis of trends in protein sequences and characteristic chemical patterns on protein surfaces, we designed four-monomer random heteropolymers to mimic intrinsically disordered proteins for protein solubilization and stabilization in non-native environments. The heteropolymers, with optimized composition and statistical monomer distribution, enable cell-free synthesis of membrane proteins with proper protein folding for transport and enzyme-containing plastics for toxin bioremediation. Controlling the statistical monomer distribution in a heteropolymer, rather than the specific monomer sequence, affords a new strategy to interface with biological systems for protein-based biomaterials.

Poly(1,2,3-triazolium)s: a new class of functional polymer electrolytes.

Poly(ionic liquid)s (PILs) are a unique class of polyelectrolytes having properties suited for modern technological applications such as electrochemical devices (batteries, supercapacitors, light-emitting electrochemical cells), ion-gated field effect transistors, electrochromic devices, fuel cells, dye sensitized solar cells, catalysis, or soft robotics. Their structure and properties can be finely tuned by unlimited combinations issued from extended pools of cationic and anionic building blocks. In a constant quest for the development of solid polymer electrolytes with enhanced physical, mechanical and (electro)chemical properties, a new class of PILs based on 1,2,3-triazolium cations has been recently developed. Their preparation takes advantage of the beneficial features of the multiple combinations between the Click chemistry philosophy with macromolecular engineering techniques to afford tunable and highly functional ion conducting materials thus stretching out the actual boundaries of PILs macromolecular design. This feature article summarizes the different strategies developed so far for the synthesis of 1,2,3-triazolium-based PILs (TPILs) since their first introduction in 2013.

Enhancing Properties of Anionic Poly(ionic liquid)s with 1,2,3-Triazolium Counter Cations.

A series of anionic poly(ionic liquid)s with 1,2,3-triazolium counter cations are prepared by cation exchange between tailormade 1,3,4-trialkylated-1,2,3-triazolium iodides and a polystyrene derivative having pendant potassium bis(trifluoromethylsulfonyl)imide groups. The physical and ion-conducting properties of the resulting materials are compared to the parent potassium-containing polyelectrolyte based on 1H NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and broadband dielectric spectroscopy (BDS) measurements. Substitution of the potassium counter cation by 1,2,3-triazolium charge carriers affords polyelectrolytes with improved processability (broader solubility and removal of the crystalline behavior) as well as a substantial increase in anhydrous ionic conductivity.

UV-Patterning of Ion Conducting Negative Tone Photoresists Using Azide-Functionalized Poly(Ionic Liquid)s.

The patterning of solid electrolytes that builds upon traditional fabrication of semiconductors is described. An azide-functionalized poly(1,2,3-triazolium ionic liquid) is used as an ion conducting negative tone photoresist. After UV-irradiation through an optical mask, micron-scaled, patterned, solid polyelectrolyte layers with controlled sizes and shapes are obtained. Furthermore, alkylation of poly(1,2,3-triazole)s can be generalized to the synthesis of poly(ionic liquid)s with a tunable amount of pendant functionalities.