Maitane Salsamendi

Single-Ion Block Copoly(ionic liquid)s as Electrolytes for All-Solid State Lithium Batteries

Polymer electrolytes have been proposed as replacement for conventional liquid electrolytes in lithium-ion batteries (LIBs) due to their intrinsic enhanced safety. Nevertheless, the power delivery of these materials is limited by the concentration gradient of the lithium salt. Single-ion conducting polyelectrolytes represent the ideal solution since their nature prevents polarization phenomena. Herein, the preparation of a new family of single-ion conducting block copolymer polyelectrolytes via reversible addition-fragmentation chain transfer polymerization technique is reported. These copolymers comprise poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) and poly(ethylene glycol) methyl ether methacrylate blocks. The obtained polyelectrolytes show low Tg values in the range of -61 to 0.6 °C, comparatively high ionic conductivity (up to 2.3 × 10(-6) and 1.2 × 10(-5) S cm(-1) at 25 and 55 °C, respectively), wide electrochemical stability (up to 4.5 V versus Li(+)/Li), and a lithium-ion transference number close to unity (0.83). Owing to the combination of all mentioned properties, the prepared polymer materials were used as solid polyelectrolytes and as binders in the elaboration of lithium-metal battery prototypes with high charge/discharge efficiency and excellent specific capacity (up to 130 mAh g(-1)) at C/15 rate.

Synthesis of 2‐(Selenophen‐2‐yl)pyrroles and Their Electropolymerization to Electrochromic Nanofilms

Bridging pyrrole and selenophene chemistries: Molecular assemblies have been developed that allow scrutiny of the electronic communication between pyrrole and selenophene nuclei. Divergent syntheses of 2-(selenophen-2-yl)pyrroles and their N-vinyl derivatives from available 2-acylselenophenes and acetylenes in a one-pot procedure have been devised (see scheme), which provide access to these exotic heterocyclic ensembles.The divergent syntheses of 2-(selenophen-2-yl)pyrroles and their N-vinyl derivatives from available 2-acylselenophenes and acetylenes in a one-pot procedure make these exotic heterocyclic ensembles accessible. Now we face a potentially vast area for exploration with a great diversity of far-reaching consequences including conducting electrochromic polymers with repeating of pyrrole and selenophene units (emerging rivalry for polypyrroles and polyselenophenes), the synthesis of functionalized pyrrole-selenophene assembles for advanced materials, biochemistry and medicine, exciting models for theory of polymer conductivity.

Polymerization kinetics of a fluorinated monomer under confinement in AAO nanocavities

In this work we show for the first time the kinetic study of the radical polymerization of a fluorinated acrylic monomer (MFA) in the confinement of anodic aluminum oxide (AAO) nanocavities. AAO templates with different pore sizes were used as nanoreactors and polymerization kinetics were studied in situ by Raman spectroscopy and in bulk by differential scanning calorimetry (DSC). Afterwards, a mathematical model that describes the effect of nanoconfinement on the polymerization kinetics was derived. Furthermore, similar nanostructures were observed by SEM when in bulk polymerized PFA was infiltrated into the AAO nanocavities. Superhydrophobic surfaces were achieved with the water contact angle of 159°, much higher than its analogous non-nanostructured PFA, 114°. The “lotus effect” was observed in the superhydrophobic surface which has a low sliding angle of 8°.

An investigation into the nature and potential of in-situ surfactants for low energy miniemulsification

HYPOTHESIS It has been reported that surfactants generated in-situ are more efficient than their preformed analogues in preparation of miniemulsions for application in miniemulsion polymerization but conflicting experimental evidence exists over their use. Herein, the potential of preparing miniemulsions using in-situ generated surfactants is evaluated using KOH/oleic acid as a model system. EXPERIMENTS The kinetics of miniemulsification using either preformed or in-situ generated potassium oleate were evaluated by monitoring the evolution of droplet size, pH and conductivity during miniemulsification using sonication. Subsequently, the kinetics of surfactant adsorption to the monomer/water interface were studied using dynamic interfacial tension measurements. Finally, the ability of in-situ generated potassium oleate to produce miniemulsions under low shear was evaluated under a range of conditions. FINDINGS No difference in the evolution of droplet size, pH or conductivity was observed between the two surfactant systems when sonication was applied. Dynamic interfacial tension measurements showed that using in-situ generated potassium oleate, interfacial tension is significantly lower initially, but at long times the two surfactant systems reach similar values. Low shear emulsification by in-situ generated potassium oleate resulted in a bimodal droplet distribution. Only at very low oil contents with high surfactant concentration is the number of nanometer sized droplets large enough to account for a miniemulsion polymerization mechanism.

Polymeric Ion Gels: Preparation Methods, Characterization, and Applications

In this chapter, we have summarized the preparation methods, properties, and applications of ion gels. Ion gels or ionogels are a new type of gels where the liquid phase, percolating throughout the solid phase, is an ionic liquid. Ion gels are attractive materials especially due to its good ionic conductivity, electrochemical and chemical stability, nonflammability, thermal stability, negligible vapor pressure, solid-like behavior, and tunable flexibility. Inorganic or polymeric materials can be used as gelators in combination with ionic liquids to synthesize ion gels. However, this chapter is mainly focused in the development of ion gels using polymeric materials such as triblock copolymers, fluorinated polymers, or poly(ionic liquids) as gelators.

Catechol End-Functionalized Polylactide by Organocatalyzed Ring-Opening Polymerization

There is a great interest in incorporating catechol moieties into polymers in a controlled manner due to their interesting properties, such as the promotion of adhesion, redox activity or bioactivity. One possibility is to incorporate the catechol as end-group in a polymer chain using a functional initiator by means of controlled polymerization strategies. Nevertheless, the instability of catechol moieties under oxygen and basic pH requires tedious protection and deprotection steps to perform the polymerization in a controlled fashion. In the present work, we explore the organocatalyzed synthesis of catechol end-functional, semi-telechelic polylactide (PLLA) using non-protected dopamine, catechol molecule containing a primary amine, as initiator. NMR and SEC-IR results showed that in the presence of a weak organic base such as triethylamine, the ring-opening polymerization (ROP) of lactide takes place in a controlled manner without need of protecting the cathechol units. To further confirm the end-group fidelity the catechol containing PLLA was characterized by Cyclic Voltammetry and MALDI-TOF confirming the absence of side reaction during the polymerization. In order to exploit the potential of catechol moieties, catechol end-group of PLLA was oxidized to quinone and further reacted with aliphatic amines. In addition, we also confirmed the ability of catechol functionalized PLLA to reduce metal ions to metal nanoparticles to obtain well distributed silver nanoparticles. It is expected that this new route of preparing catechol-PLLA polymers without protection will increase the accessibility of catechol containing biodegradable polymers by ROP.

Covalent-Bonded Reduced Graphene Oxide–Fluorescein Complex as a Substrate for Extrinsic SERS Measurements

When graphene is used as SERS substrates, it contributes to the chemical mechanism (CM) of enhancement of Raman signal, owing to which the detection limit is very low (lower than mM content of probe molecules). The CM of enhancement depends largely on the interactions between the substrate and the probe molecules. Therefore, in this work, we have investigated the possibility of increasing the SERS activity of graphene by improving the interaction between the probe molecule and the graphene substrate by establishing exclusively strong covalent bonding between them. Fluorescein (Fl) was selected as a probe molecule because it is one of the most commonly used fluorophore in bioscience. As a graphene substrate, reduced graphene oxide (rGO) platelets were used. In addition, silver nanoparticles (AgNPs) were added onto the hybrids to further increase the enhancement by electromagnetic mechanism. Highly enhanced Raman signal of Fl onto neat rGO was achieved for micromolar concentration of the probe molecules. This was attributed to the covalent bonding between them, which introduced hole doping to rGO, decreasing the Fermi level of rGO and bringing it more closely to the LUMO of Fl. This induces aligning of their energy levels, resulting in higher contribution of the nonresonance effect to the charge transfer mechanism of enhancement, which, in this case, occurred intramolecularly. When AgNPs were added onto the rGO substrate, the expected enhancement performance was not observed. On the one hand, this was attributed to small size (∼20 nm) of AgNPs and lack of aggregates and, on the other, due to the unusually high contribution of CM determined.