Dynamic Ion Gels from the Complex Coacervation of Oppositely Charged Poly(ionic liquid)s.

A cationic poly(ionic liquid) (PIL) with pendent butyl imidazolium cations and free bis(trifluoromethylsulfonyl)imide (TFSI) anions and an anionic PIL with pendent TFSI anions and free 1-butyl-3-methylimidazolium cations are synthesized by postpolymerization chemical modification and reversible addition-fragmentation chain-transfer radical copolymerization, respectively. Upon mixing solutions of these two PILs in acetone with stoichiometric amounts of ion pairs, ionic exchanges induce coacervation and, after solvent evaporation, lead to the formation of a dynamic ion gel (DIG) and the concomitant release of free [1-methyl-3-butyl imidazolium]TFSI ionic liquid (IL). A comparison of thermal (), ion conducting (σ), and viscoelastic (elastic moduli (')) properties for DIGs and their parent polyelectrolytes, as well as extracted and IL-doped DIGs, demonstrates the formation of ionic cross-links and the ability to easily produce polymer electrolytes with enhanced ionic conductivity (σ up to 4.

1,3,4,5-Tetrasubstituted Poly(1,2,3-triazolium) Obtained through Metal-Free AA+BB Polyaddition of a Diazide and an Activated Internal Dialkyne.

A tetra(ethylene glycol)-based 1,3,4,5-tetrasubstituted poly(1,2,3-triazolium) is synthesized in two steps including: i) the catalyst-free polyaddition of a diazide and an activated internal dialkyne and ii) the N-alkylation of the resulting 1,2,3-triazole groups. In order to provide detailed structure/properties correlations different analogs are also synthesized. First, parent poly(1,2,3-triazole)s are obtained via AA+BB polyaddition using copper(I)-catalyzed alkyne-azide cycloaddition or metal-free thermal alkyne-azide cycloaddition (TAAC).

Interface Manipulations Using Cross-Linked Underlayers and Surface-Active Diblock Copolymers to Extend Morphological Diversity in High-χ Diblock Copolymer Thin Films.

Top and bottom interfaces of high-χ cylinder-forming polystyrene--maltoheptaose (PSMH) diblock copolymer (BCP) thin films are manipulated using cross-linked copolymer underlayers and a fluorinated phase-preferential surface-active polymer (SAP) additive to direct the self-assembly (both morphology and orientation) of BCP microdomains into sub-10 nm patterns. A series of four photo-cross-linkable statistical copolymers with various contents of styrene, a 4-vinylbenzyl azide cross-linker, and a carbohydrate-based acrylamide are processed into 15 nm-thick cross-linked passivation layers on silicon substrates. A partially fluorinated analogue of the PSMH phase-preferential SAP additive is designed to tune the surface energy of the top interface.

Cross-linked polymer microparticles with tunable surface properties by the combination of suspension free radical copolymerization and Click chemistry.

We propose a general, versatile and broad in scope two-steps approach for the elaboration of cross-linked polymer microparticles (µPs) with tunable functionalities and surface properties. Surface-functionalized cross-linked polymer µPs with diameter in the 80 μm range are prepared by the combination of: 1) suspension free radical copolymerization of styrene, propargyl methacrylate and 1,6-hexanediol dimethacrylate, 2) subsequent covalent tethering of a variety of azide-functionalized moieties (i.e.

Viscoelasticity-Induced Onset of Slip at the Wall for Polymer Fluids.

The progressive onset of slip at the wall, which corresponds to a slip length increasing with the solicitation time before reaching a plateau, has been investigated for model viscoelastic polymer solutions, allowing one to vary the longest relaxation time while keeping constant solid-fluid interactions. A hydrodynamic model based on a Maxwell fluid and the classical Navier's hypothesis of a linear response for the friction stress at the interface fully accounts for the data. In the limit of the linear viscoelasticity of the fluid, we could postulate a Newtonian response for the interfacial friction coefficient, reflecting the local character of solid-liquid friction mechanisms.

Access to Thermodynamic and Viscoelastic Properties of Poly(ionic liquid)s Using High-Pressure Conductivity Measurements.

In this paper, we examine the transport properties of a 1,2,3-triazolium-based poly(ionic liquid) (PIL) at ambient and elevated pressure up to 475 MPa. We show that the isothermal and isobaric conductivity measurements analyzed in the 3D plane give a unique possibility to estimate the thermodynamic (isothermal compressibility and thermal expansion coefficient) properties for PILs having a charge transport fully controlled by viscosity. This result, providing a direct connection between thermodynamic and dynamic properties of PILs, is of significant importance for both material scientists and practical applications.

Reusable Enzymatic Fiber Mats for Neurotoxin Remediation in Water.

Highly effective and reusable organophosphorus hydrolase (OPH)-loaded fiber mats have been fabricated that are capable of degrading toxic organophosphates (OPs) over a broad range of relevant concentrations (from 8 to 8250 ppm). The inherent fragility of enzymes, a major impediment in their incorporation into technologically relevant materials, was overcome while retaining their high catalytic efficiency, selectivity, and sensitivity via a random heteropolymers (RHP) approach. Kinetic analysis guides the design of polycaprolactone matrix morphology from films to fibers, facilitating substrate diffusion in the material.

Temperature-Controlled Slip of Polymer Melts on Ideal Substrates.

The temperature dependence of the hydrodynamic boundary condition between a polydimethylsiloxane melt and two different nonattractive surfaces made of either an octadecyltrichlorosilane self-assembled monolayer or a grafted layer of short polydimethylsiloxane chains has been characterized. We observe a slip length proportional to the fluid viscosity. The temperature dependence is deeply influenced by the surfaces.

Sensing adsorption kinetics through slip velocity measurements of polymer melts.

The evolution over time of the nonlinear slip behavior of a polydimethylsiloxane (PDMS) polymer melt on a weakly adsorbing surface made of short non-entangled PDMS chains densely end-grafted to the surface of a fused silica prism has been measured. The critical shear rate at which the melt enters the nonlinear slip regime has been shown to increase with time. The adsorption kinetics of the melt on the same surface has been determined independently using ellipsometry.

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.

Friction of Polymers: from PDMS Melts to PDMS Elastomers.

The slip behavior of polydimethylsiloxane (PDMS) polymer melts flowing on weakly adsorbing surfaces made of short nonentangled PDMS chains densely end-grafted to silica has been characterized. For high enough shear rates, slip lengths proportional to the bulk fluid viscosity have been observed, in agreement with Navier's interfacial equation and demonstrating that the interfacial Navier's friction coefficient is a local quantity, independent of the polymer molecular weight. Comparing the interfacial shear stresses deduced from these measured slip lengths to available friction stress measured for cross-linked PDMS elastomers, we further demonstrate the local character of the friction coefficient and compare its value to the monomer-monomer friction.

Fluorinated Poly(ionic liquid) Diblock Copolymers Obtained by Cobalt-Mediated Radical Polymerization-Induced Self-Assembly.

Poly(ionic liquid)s (PILs) have attracted considerable attention as innovative single-ion solid polyelectrolytes (SPEs) in substitution to the more conventional electrolytes for a variety of electrochemical devices. Herein, we report the precise synthesis, characterization, and use as single-ion SPEs of a novel double PIL-based amphiphilic diblock copolymer (BCP), i.e.

Influence of grafting on the glass transition temperature of PS thin films.

We present an investigation of the effect of the interaction between a thin polystyrene film and its supporting substrate on its glass transition temperature ([Formula: see text]). We modulate this interaction by depositing the film on end-tethered polystyrene grafted layers of controlled molecular parameters. By comparing [Formula: see text] measurements versus film thickness for films deposited on different grafted layers and films deposited directly on a silicon substrate, we can conclude that there is no important effect of the film-subtrate interaction.

Enhanced Ionic Conductivity of a 1,2,3-Triazolium-Based Poly(siloxane ionic liquid) Homopolymer.

A 1,2,3-triazolium-based poly(siloxane ionic liquid) (PSIL) is synthesized by UV-triggered thiol-ene ligation between a poly[(mercaptopropyl)methylsiloxane] and a tailor-made vinyl-functionalized triethylene glycol-based 1,2,3-triazolium ionic liquid. The quantitative nature of the thiol-ene coupling is demonstrated by H and C NMR, whereas properties of this new PSIL are discussed based on solubility, size exclusion chromatography, differential scanning calorimetry, thermogravimetric analysis, and broadband dielectric spectroscopy measurements. Besides exhibiting low glass transition temperature ( = -62 °C) and high thermal stability ( = 284 °C), this new class of poly(1,2,3-triazolium) demonstrates the highest value of bulk anhydrous ionic conductivity reported to date for PILs (σ = 7 × 10 S cm at 30 °C).

1,2,3-Triazolium-Based Epoxy-Amine Networks: Ion-Conducting Polymer Electrolytes.

A diepoxy-functionalized 1,2,3-triazolium ionic liquid is synthesized in three steps and used in combination with a poly(propylene glycol) diamine to obtain ion-conducting epoxy-amine networks (EANs). The curing kinetics are followed by Fourier transform infrared spectroscopy, while the physical, mechanical, and ion-conducting properties of the resulting networks are studied by swelling experiments, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and broadband dielectric spectroscopy. The curing kinetics and thermomechanical properties of this system are relatively similar to those of conventional DGEBA- (bisphenol A diglycidyl ether)-based EANs with low glass transition temperature (Tg = -44 and -52 °C, respectively) characteristic of rubbery polymer networks.

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.

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.

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.

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 H 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.

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.

Toward tunable amphiphilic copolymers via CuAAC click chemistry of oligocaprolactones onto starch backbone.

Starch-based tunable amphiphilic copolymers are easily obtained by grafting polycaprolactone chains via 1,3 dipolar Copper-Catalyzed Azide-Alkyne Cycloaddition (click chemistry CuAAC), starting from propargylated starch and azido oligocaprolactones with different chain lengths as the precursors. The copolymers are characterized by (1)H and (13)C NMR, from which a degree of substitution of starch can tentatively be deduced. Besides these bulk characterizations, the surface of the functionalized starch is also characterized by XPS which confirms the triazole formation, particularly through the deconvolution of the N 1s peak, and by ToF-SIMS which, not only confirms the surface modification, but also highlights the disappearance of the Cu(+) cations.

RAFT polymerization of bio-based 1-vinyl-4-dianhydrohexitol-1,2,3-triazole stereoisomers obtained via click chemistry.

Four 1-vinyl-4-dianhydrohexitol-1,2,3-triazole stereoisomers are prepared from isomannide, isoidide, and isosorbide using an alkylation/CuAAC-ligation/elimination three-step strategy. After characterization of the monomers by NMR, differential scanning calorimetry (DSC), and high-resolution mass spectrometry (HRMS), the corresponding stereocontrolled poly(1-vinyl-4-dianhydrohexitol-1,2,3-triazole)s are obtained by RAFT polymerization using a xanthate chain transfer agent. A systematic investigation of the structure-properties relationship of both the monomers and polymers highlights the significant impact of the dianhydrohexitols stereochemistry on their physical properties (1H and 13C NMR chemical shifts, physical state, Tg, thermal stability and solubility).

Biodegradable, multi-layered coatings for controlled release of small molecules.

Incorporation of orthogonal functional groups into biodegradable polymers permits the fabrication of multi-layered thin films with improved adhesion and tunable degradation profiles. The bi-layer structure also allows for accurate control over small molecule release.

Precise synthesis of molecularly defined oligomers and polymers by orthogonal iterative divergent/convergent approaches.

The synthesis of perfectly defined (macro)molecules has been a constant challenge for polymer and organic chemists. This paper highlights the main applications of the iterative divergent/convergent approach for the synthesis of discrete mass oligomers and polymers. We will discuss the orthogonal deprotection and coupling strategies involved in this powerful strategy where chain length doubles at each iteration and which has been applied to the synthesis of conjugated rigid rods as well as amorphous and crystalline oligomers and polymers.