Ionic Nanocomposites Research Articles

Multifunctional Nanocomposite Yield-Stress Fluids for Printable and Stretchable Electronics.

Compliant materials are crucial for stretchable electronics. Stretchable solids and gels have limitations in deformability and durability, whereas active liquids struggle to create complex devices. This study presents multifunctional yield-stress fluids as printable ink materials to construct stretchable electronic devices. Ionic nanocomposites comprise silica nanoparticles and ion liquids, while electrical nanocomposites use the natural oxidation of liquid metals to produce gallium oxide nanoflake additives. These nanocomposite inks can be printed on an elastomer substrate and stay in a solid state for easy encapsulation. However, their transition into a liquid state during stretching allows ultrahigh deformability up to the fracture strain of the elastomer. The ionic inks produce strain sensors with high stretchability and temperature sensors with high sensitivity of 7% °C-1. Smart gloves are further created by integrating these sensors with printed electrical interconnects, demonstrating bimodal detection of temperatures and hand gestures. The nanocomposite yield-stress fluids combine the desirable qualities of solids and liquids for stretchable devices and systems.

Electrochemical determination of fenitrothion pesticide based on ultrathin manganese oxide nanowires/molybdenum titanium carbide MXene ionic nanocomposite and molecularly imprinting polymer

A novel molecularly imprinted electrochemical sensor is presented based on one-dimensional ultrathin manganese oxide nanowires/two-dimensional molybdenum titanium carbide MXene (MnO2NWs@Mo2TiC2 MXene) for fenitrothion (FEN) determination. After the synthesis of MnO2NWs@Mo2TiC2 MXene ionic nanocomposite was successfully completed with a facile hydrothermal and the pillaring methods, a new type molecular imprinted electrochemical sensor based on MnO2NWs@Mo2TiC2 MXene was constructed with cyclic voltammetry (CV) polymerization including pyrrole monomer and FEN target molecule. After the characterization studies including spectroscopic, electrochemical and microscopic methods, the analytical applications of the prepared sensor were performed. A linearity of 1.0×10−9–2.0×10−8 mol L−1 was obtained and the values of the quantification limit (LOQ) and the detection limit (LOD) were 1.0×10−9 mol L−1 and 3.0×10−10 mol L−1, respectively. The studies of selectivity, stability and reproducibility of the constructed sensor based on MnO2NWs@Mo2TiC2 nanocomposite and molecularly imprinting polymer (MIP) were carried out in detail. Finally, the developed sensor was applied to white flour samples with the values close to 100%.Graphical

From Ionic Nanoparticle Organic Hybrids to Ionic Nanocomposites: Structure, Dynamics, and Properties: A Review.

Ionic nanoparticle organic hybrids have been the focus of research for almost 20 years, however the substitution of ionic canopy by an ionic-entangled polymer matrix was implemented only recently, and can lead to the formulation of ionic nanocomposites. The functionalization of nanoparticle surface by covalently grafting a charged ligand (corona) interacting electrostatically with the oppositely charged canopy (polymer matrix) can promote the dispersion state and stability which are prerequisites for property "tuning", polymer reinforcement, and fabrication of high-performance nanocomposites. Different types of nanoparticle, shape (spherical or anisotropic), loading, graft corona, polymer matrix type, charge density, molecular weight, can influence the nanoparticle dispersion state, and can alter the rheological, mechanical, electrical, self-healing, and shape-memory behavior of ionic nanocomposites. Such ionic nanocomposites can offer new properties and design possibilities in comparison to traditional polymer nanocomposites. However, to achieve a technological breakthrough by designing and developing such ionic nanomaterials, a synergy between experiments and simulation methods is necessary in order to obtain a fundamental understanding of the underlying physics and chemistry. Although there are a few coarse-grained simulation efforts to disclose the underlying physics, atomistic models and simulations that could shed light on the interphase, effect of polymer and nanoparticle chemistry on behavior, are completely absent.

Influence of photooxidation on ionic reversible interactions of ionic poly(ether urethane)/silica hybrids

Organic-inorganic hybrids that combine the reversible nature of electrostatic interactions present in ionic systems with the reinforcement ability of nanoparticles in nanocomposites have the potential to revolutionize a wide spectrum of technologies. However, the prediction of their service lifetime under photooxidative conditions has remained elusive. In this paper, the accelerated environmental ageing of ionic hybrid materials made by combining imidazolium-functionalized poly(ethylene glycol)-based polyurethane (im-PU) and surface-modified sulfonate silica nanoparticles (SiO2-SO3H) is addressed. Since the resulting ionic nanocomposites are dynamic, the present contribution aims to elucidate their temporal behavior and precisely distinguish the contribution of the nanoparticles addition to the photochemical behavior. Although the addition of SiO2-SO3H nanoparticles within im-PU matrix led to faster photooxidative degradation, the ionic imidazolium-sulfonate crosslinks are thought to be sustained under photooxidative conditions. The results further suggest that the molecular weight loss and the resulting ductile-to-brittle transition for the ionic hybrid under atmospheric ageing conditions are attributed to severe chain scissions into the im-PU backbone in the presence of SiO2-SO3H nanoparticles. Overall, the present investigation suggests that the silica nanoparticles addition is responsible for the prodegradant effect rather than the presence of reversible ionic interactions in the system. The present work thus provides a deeper understanding about the crucial role of the incorporation of dynamic linkages within ionic nanocomposites during photochemical ageing and can aid the future design and use of these systems.

Defect-enhanced selective ion transport in an ionic nanocomposite for efficient energy harvesting from moisture

Defect-enhanced selective ion transport within a generator made from an ionic liquid film supported by ZIF-8-based membranes enables high-performance moisture energy harvesting.

Mastering Superior Performance Origins of Ionic Polyurethane/Silica Hybrids

Even though reversible interactions within ionic hydrogels are well-studied, underlying mechanisms responsible for the high-value added performance of ionic nanocomposites remain almost unexplored. We herein propose a fundamental understanding aiming at elucidating the mechanism behind the reversible breaking and reformation of ionic bonding in the case of organic–inorganic hybrids made of a combination of imidazolium-functionalized poly(ethylene glycol)-based polyurethane (im-PU) and surface-modified sulfonate silica nanoparticles (SiO2–SO3H). Such ionic hybrids already demonstrated unique features related to the presence of electrostatic interactions, but the underlying mechanisms governing the overall material performance have never been discussed. To dissociate the reinforcement role of nanoparticles and ionic interactions, either standard nonionic SiO2 or ionic SiO2–SO3H nanoparticles were introduced into im-PU. Mechanical performances, thermal transitions, relaxation processes, and the morphology of the hybrids were deeply investigated to better comprehend the mechanisms at the origin of the ionic material reinforcement. In addition, a mechanistic investigation is proposed to quantify the dissipation energy ability of the as-proposed ionic hybrids, and an approach is presented to identify a characteristic time for restoration of reversible ionic bonds under different loading scenarios.

Sulfonic acid-functionalized magnetic carbon nitride as highly efficient ionic composite for sustainable assembly of 1,2,3-triazoles

An efficient and straightforward method for constructing of biologically active 4-aryl-NH-1,2,3-triazoles by the 1,3-dipolar cycloaddition reaction of β-nitrostyrene and sodium azide in the presence of acidic graphitic carbon nitride (Fe3O4@g-C3N4–SO3H) ionic nanocomposite has developed. Using a magnetically recoverable acidic ionic catalyst allows eco-friendly and facile conversion and simplifies experimental setup and work-up procedure that enables the direct synthesis of triazole derivatives under mild conditions. The designed catalytic system provides a broader scope under short reaction times in good to excellent yields. Fe3O4@g-C3N4–SO3H could be simply recovered by magnetic separation using an external magnet, maintaining stable activity up to five cycles without appreciable loss of activity.

Polymer Conformations, Entanglements and Dynamics in Ionic Nanocomposites: A Molecular Dynamics Study.

We investigate nanoparticle (NP) dispersion, polymer conformations, entanglements and dynamics in ionic nanocomposites. To this end, we study nanocomposite systems with various spherical NP loadings, three different molecular weights, two different Bjerrum lengths, and two types of charge-sequenced polymers by means of molecular dynamics simulations. NP dispersion can be achieved in either oligomeric or entangled polymeric matrices due to the presence of electrostatic interactions. We show that the overall conformations of ionic oligomer chains, as characterized by their radii of gyration, are affected by the presence and the amount of charged NPs, while the dimensions of charged entangled polymers remain unperturbed. Both the dynamical behavior of polymers and NPs, and the lifetime and amount of temporary crosslinks, are found to depend on the ratio between the Bjerrum length and characteristic distance between charged monomers. Polymer–polymer entanglements start to decrease beyond a certain NP loading. The dynamics of ionic NPs and polymers is very different compared with their non-ionic counterparts. Specifically, ionic NP dynamics is getting enhanced in entangled matrices and also accelerates with the increase of NP loading.

Mechanistic insights on ultra-tough polylactide-based ionic nanocomposites

We report the synthesis and characterization of ultra-tough polylactide-based ionic nanocomposites via melt-blending of commercial polylactide (PLA), imidazolium-functionalized poly(ethylene glycol)-based polyurethane (im-PU) and surface-modified sulfonated silica nanoparticles (SiO2–SO3H) using extrusion techniques. The proximity of bulky pendant imidazolium cationic sites attached onto the highly functionalized polyurethane to the anionic sulfonate groups at the silica nanoparticle surface readily allow maximizing dynamic ionic interactions within the resulting PLA-based materials. This new design leads to a unique property profile that combines ultra-toughness (no break) and ductility (up to 150%), without critical loss of stiffness as well as improved thermal stability (up to 40 °C higher compared to neat PLA). In addition, we present a detailed mechanistic study aiming at elucidating the energy-dissipative toughening in these PLA/im-PU/SiO2–SO3H blends under quasi-static and high-speed loadings (ca. impact, tensile, 3-points bending). Relying on Small-Angle X-Ray Scattering (SAXS), creep and rheological measurements, a toughening mechanism is finally proposed to account for the impact behavior of the resulting ionic nanocomposites.

An ultra-stretchable, highly sensitive and biocompatible capacitive strain sensor from an ionic nanocomposite for on-skin monitoring.

Flexible strain sensors that can be comfortably attached onto the skin for real-time and accurate detection of physiological signals are particularly important for the realization of healthcare, soft robotics and human-machine interfacing. It is still challenging to develop strain sensors that satisfy both high stretchability and high sensitivity. Here, we demonstrate an ultra-stretchable, highly sensitive and biocompatible capacitive-type strain sensor based on a nanocomposite containing ionic hydrogels and silver nanofibers (AgNFs). The sensor exhibits an ultra-high stretchability of 1000% and high sensitivity with a maximum gauge factor (GF) of up to 165. We find that the incorporation of AgNFs greatly increases the electrical-double layer (EDL) area at the hydrogel/metal interface and hence enhances by 3 orders of magnitude the strain sensitivity. With a short response time and good operation stability, the sensor and its matrix were successfully applied to monitor various physiological signals such as arm and finger motions, pulse, electrocardiographs (ECG), breath, speaking and emotion changes.

Miscibility and Nanoparticle Diffusion in Ionic Nanocomposites.

We investigate the effect of various spherical nanoparticles in a polymer matrix on dispersion, chain dimensions and entanglements for ionic nanocomposites at dilute and high nanoparticle loading by means of molecular dynamics simulations. The nanoparticle dispersion can be achieved in oligomer matrices due to the presence of electrostatic interactions. We show that the overall configuration of ionic oligomer chains, as characterized by their radii of gyration, can be perturbed at dilute nanoparticle loading by the presence of charged nanoparticles. In addition, the nanoparticle’s diffusivity is reduced due to the electrostatic interactions, in comparison to conventional nanocomposites where the electrostatic interaction is absent. The charged nanoparticles are found to move by a hopping mechanism.

Nanocomposite electrolytes for lithium batteries with reduced flammability

We report a family of flame-retardant electrolytes for lithium batteries based on ionic nanocomposites. The nanocomposites are synthesized in one pot by dispersing SiO2 nanoparticles charge-balanced by both Li ions and mono-amino-terminated polyether (PEO-b-PPO-NH3+) in an oligomeric PEO matrix. The Li+ and PEO-b-PPO-NH3+ ions lead to enhanced Li+ transference number and compatibility with the PEO matrix, respectively. The nanocomposite electrolyte containing 40% mass fraction of silica shows a notable electrochemical stability window of more than 6 V in contact with Lithium and high Li+ transference number over 0.5. Rheology measurements demonstrate the tunability of the system from liquid to gel-like as the silica mass fraction percentage increases from 0 to 40% while the conductivity remains almost constant. Thermal gravimetric and microscale combustion calorimeter measurements of the nanocomposites show decreased rate of mass loss and heat release rate compared to neat electrolyte. Finally, the fire retardancy of the nanocomposites measured by directly observing the formation and sustainability of flame, when exposed to direct fire, make them promising candidates in the ever-growing quest for safe lithium batteries.

Ultra-stretchable ionic nanocomposites: from dynamic bonding to multi-responsive behavior

We demonstrate a novel family of multi-responsive materials, i.e. nanocomposites built on ionic interactions, that combine enhanced mechanical performances and reversibility endowed to dynamic systems.

Preparation and mechanical properties of a transparent ionic nanocomposite hydrogel

The poor stability of clay dispersion in the presence of ionic species presents a challenge for preparing a transparent ionic nanocomposite (NC) hydrogel with the desired strength. A transparent ionic NC hydrogel was successfully prepared by in situ copolymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and acrylamide (AAm) in the Laponite dispersion. AMPS played a dominant role in the dispersion of Laponite. Mechanical analyses demonstrated that this type of hydrogel has a combination of high tensile strength and excellent stretch ability. An increase in AMPS content made a big contribution to the tensibility, while an increase in clay content improved the elastic modulus. The ionic NC hydrogel exhibited a self-healing property, which occurred autonomously, without any outside intervention. The results showed that physical interaction among the NC hydrogels can be recovered. This work is a continuation of our previous efforts on the preparation and application of ionic NC hydrogels, for which there is a range of potential applications in soft and smart machines in the future.

Electroactive actuation and conductive behavior of polyaniline-impregnated blood compatible nanocomposites

Novel electrically conducting and biocompatible composite hydrogel materials comprising polyaniline (PANI) nanoparticles dispersed in a polyvinyl alcohol—g—poly (2-acrylamido-2-methyl-1-propanesulfonic acid) matrix were prepared by in situ polymerization of aniline. The prepared ionic nanocomposites were evaluated for their water-uptake capacity in distilled water and electrolyte solutions. While structural confirmation and crystalline nature of the synthesized graft copolymer was sought by Fourier transform infrared spectroscopy and X-ray diffraction techniques, respectively, morphology and dimension of PANI particles embedded into the colored optically semi-transparent polymer films were evaluated by scanning electron microscopy analysis and transmission electron microscopy. Electrical conductivity of composite hydrogels containing different percentages of PANI was determined by the LCR meter while the electroactive behavior of composite hydrogel swollen in electrolyte solution was investigated by effective bend angle measurements. Considering the potential of electrically conductive nanocomposite materials in biomedical applications, the in vitro blood compatibility of nanocomposites was investigated by employing several established in vitro test procedures.

Ionic nanocomposites based on XNBR-OMg filled with layered nanoclays

Ionic elastomers based on carboxylated nitrile rubber (XNBR) crosslinked with magnesium oxide (OMg) and filled with layered nanoclays have been prepared. Two types of nanofillers were employed: a commercial one (Cloisite 15 A) and the other prepared in our laboratory (BCA–ODA). The properties of raw and vulcanized compounds have been studied in order to elucidate the effect of layered nanoclays. X-ray diffraction analysis shows that during compounding and crosslinking the macromolecular chains of rubber were intercalated in a commercial nanofiller, whilst our nanoclay was exfoliated. However, this fact does not affect the properties of compounds homogeneously. Vulcanization parameters, Mooney viscosity and decay and rheological properties were affected depending on the filler type. Mechanical properties were not significantly varied, but glass transition temperature and ionic transition temperature were shifted in comparison with those of the unfilled compound.

PEI-alginate nanocomposites as efficient in vitro gene transfection agents

The positive charge on PEI was partially shielded by forming ionic nanocomposites with a polysaccharide, alginic acid, in aqueous solution, bypassing tedious chemical synthesis. The content of alginic acid was varied systematically to obtain a series of nanocomposites. The nanocomposites were first characterized by assessing the surface charge (zeta potential), size (DLS) and morphology (AFM) followed by evaluation for their DNA interaction ability, cytotoxicity and transfection efficiency on various cell lines. The transfection efficiency of PEI-alginate (6.26%) nanocomposites improved dramatically (2–16-fold over native PEI) in all the cell lines studied. However, a decrease in transfection efficiency was observed on deviating from this optimal concentration of alginic acid in nanocomposites. Cytotoxicity of PEI-alginate/DNA complexes was nearly abolished on increasing the concentration of alginic acid in nanocomposites. PEI-alginate (6.26%) nanocomposites also delivered SiRNAs efficiently into mammalian cells, resulting in 80% suppression of GFP expression. The cellular uptake and endosomal escape of PEI-alginate nanocomposites and PEI were found to follow a similar route when transfection was carried out in presence of chloroquine, bafilomycin A1, cytochalasin B and methyl-β-cyclodextrin. The results demonstrate a versatile vector that can be used for efficient cytoplasmic delivery of a broad range of nucleic acids.

Improved dye-sensitized solar cells using ionic nanocomposite gel electrolytes

In this study, an effect of addition of nanoparticles into a dye-sensitized solar cells (DSCs) ionic liquid electrolyte was explored. Carbon nanotubes, other carbon nanoparticles and titanium dioxide nanoparticles were dispersed individually into a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm-TFSI) ionic liquid electrolyte by grinding. It was centrifuged to form an ionic nanocomposite gel electrolyte. The dispersion of nanoparticles resulted in a substantial increase in their viscosity. Their electric conductivity increased as well. Notable effects were obtained in photocurrent density and voltage measurements of the DSC assembled with them. Energy conversion efficiency of them was significantly improved and increased compared with a DSC using a bare ionic liquid electrolyte.

Improved dye-sensitized solar cells using ionic nanocomposite gel electrolytes

In this study, an effect of addition of nanoparticles into a dye-sensitized solar cells (DSCs) ionic liquid electrolyte was explored. Carbon nanotubes, other carbon nanoparticles and titanium dioxide nanoparticles were dispersed individually into a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm-TFSI) ionic liquid electrolyte by grinding. It was centrifuged to form an ionic nanocomposite gel electrolyte. The dispersion of nanoparticles resulted in a substantial increase in their viscosity. Their electric conductivity increased as well. Notable effects were obtained in photocurrent density and voltage measurements of the DSC assembled with them. Energy conversion efficiency of them was significantly improved and increased compared with a DSC using a bare ionic liquid electrolyte.