Titanate (IV) nanosheets (TiNSs) have a 2D structure where TiO6 octahedra are edge-linked in a lepidocrocite-type 2D latticewith chemical formula HxTi2—x/4☐x/4O4 ⦁ H2O (x~0.7; ☐, vacancy). Titanate nanosheets may be regarded as sheets with molecular thickness and infinite planar dimensions. TiNSs are typically formed via liquid-phase exfoliation of protonic titanate. In inorganic layered materials, individual layers are bound to each other by van der Waals interactions if they are neutral, and additional Coulomb interactions if they are composed of oppositely charged layers. Through liquid-phase exfoliation, these individual sheets of layered materials can be efficiently separated using an appropriate solvent, creating single-layer colloidal suspensions. Solvents must have an interaction energy with the layers that is greater than the interaction energy between two layers. In situ X-Ray diffraction data indicates that TiNSs can be treated as macromolecules with a sufficient amount of solvent in between layers so that they behave as individual sheets.
Unilamellar TiNSs have a number of unique properties, and are said to combine those of conventional titanate and titania. Structurally, they are infinite ultrathin (~0.75 nm) 2D sheets with a high density of negative surface charges originating from the oxygen atoms at the corners of the adjoint octahedrons . TiNSs may balance this anionic charge by inserting a counterionic layer between the two sheets either via layering or in aqueous solution. This electric double layer gives the material flexible interlayer distances, high cation exchange capacity, and excellent dielectric capabilities.
Typically, titanium oxide suffers from oxygen vacancies, which diminish its potential as capacitors due to vacancies acting as high-leakage paths and charge carrier traps,however, TiNSs possess Ti vacancies, which promote channels for electron transfer. When Ti vacancies are present, the effective charge felt by electrons on oxygen atoms reduces and allows less hindered electron motion.
TiNSs can act as highly efficient adsorbents and photocatalysts due to their two-dimensional geometry and structure. This phenomenon can be exploited for several applications, including the removal of metal ions and dyes from water systems.Further, TiNSs potential as an electrocatalyst may enhance fuel cell efficiency during fuel oxidation. Similarly, intercalated myoglobin is proven to be an efficient catalyst for H2O2.
TiNSs may also be used for immobilizing biomolecules. When a monolayer of hemoglobin is intercalated into TiNSs, the electron transfer between the active sites of the protein and the electrodes is amplified, and electrocatalytic activity for O2 reduction increases.[ citation needed ] In addition, heterostructured nanosheets of Fe3O4-Na2Ti3O7 can be used for protein separation. When placed in the aqueous environment at pH 6, positively charged hemoglobin binds to the nanosheets, whereas negative albumin can be detected in the supernatant.
Perhaps the most interesting application of TiNSs is in the development of a material dominated by electrostatically repulsive interactions. TiNSs exhibit maximum electrostatic repulsion when they are aligned cofacially. To create the hydrogel based on this, a solution of TiNSs is placed in a strong magnetic field where repulsive forces induce a quasi-crystalline structure. Upon irradiation with UV-light, the solution polymerizes and creates cross-linked network, which is non-covalently attached to the TiNSs.This creates a composite that resists orthogonally applied compressive forces, but easily deforms due to shear forces. TiNSs solutions of this sort may be used as an anti-vibration or vibration-isolating material and in the design of artificial cartilage.
Titanate nanosheets can also be aligned within polymer, parallel to the surface of the substrate by simple drop casting.The intercalation of polymer and orientation of nanosheets were studied by small-angle X-ray scattering (SAXS) using in-plane and symmetrical scan. SAXS mapping indicated homogeneous alignment of titanate nanosheets within polymer. The mechanical reinforcement of polyamic acid using titanate nanosheets matched with Halpin-Tsai model, which is a composite model that assume the filler is in aligned position.
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady state, although the liquid phase may still diffuse through this system. A gel has been defined phenomenologically as a soft, solid or solid-like material consisting of two or more components, one of which is a liquid, present in substantial quantity.
A dilatant material is one in which viscosity increases with the rate of shear strain. Such a shear thickening fluid, also known by the initialism STF, is an example of a non-Newtonian fluid. This behaviour is usually not observed in pure materials, but can occur in suspensions.
Polyelectrolytes are polymers whose repeating units bear an electrolyte group. Polycations and polyanions are polyelectrolytes. These groups dissociate in aqueous solutions (water), making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers and are sometimes called polysalts. Like salts, their solutions are electrically conductive. Like polymers, their solutions are often viscous. Charged molecular chains, commonly present in soft matter systems, play a fundamental role in determining structure, stability and the interactions of various molecular assemblies. Theoretical approaches to describing their statistical properties differ profoundly from those of their electrically neutral counterparts, while technological and industrial fields exploit their unique properties. Many biological molecules are polyelectrolytes. For instance, polypeptides, glycosaminoglycans, and DNA are polyelectrolytes. Both natural and synthetic polyelectrolytes are used in a variety of industries.
A Coulombic explosion is a condensed-matter physics process in which a molecule or crystal lattice is destroyed by the Coulombic repulsion between its constituent atoms. Coulombic explosions are a prominent technique in laser-based machining, and appear naturally in certain high-energy reactions.
In the area of solid state chemistry. graphite intercalation compounds are materials prepared by intercalation of diverse guests into graphite. The materials have the formula (guest)Cn where n can range from 8 to 40's. The distance between the carbon layers increases significantly upon insertion of the guests. Common guests are reducing agents such as alkali metals. Strong oxidants, such as arsenic pentafluoride also intercalate into graphite. Intercalation involves electron transfer into or out of the host. The properties of these materials differ from those of the parent graphite.
Dielectric elastomers (DEs) are smart material systems that produce large strains. They belong to the group of electroactive polymers (EAP). DE actuators (DEA) transform electric energy into mechanical work. They are lightweight and have a high elastic energy density. They have been investigated since the late 1990s. Many prototype applications exist. Every year, conferences are held in the US and Europe.
Lyotropic liquid crystals result when fat-loving and water-loving chemical compounds known as amphiphiles dissolve into a solution that behaves both like a liquid and a solid crystal. This liquid crystalline mesophase includes everyday mixtures like soap and water.
Poly(3,4-ethylenedioxythiophene)-tetramethacrylate or PEDOT-TMA is a p-type conducting polymer based on 3,4-ethylenedioxylthiophene or the EDOT monomer. It is a modification of the PEDOT structure. Advantages of this polymer relative to PEDOT are that it is dispersible in organic solvents, and it is non-corrosive. PEDOT-TMA was developed under a contract with the National Science Foundation, and it was first announced publicly on April 12, 2004. The trade name for PEDOT-TMA is Oligotron. PEDOT-TMA was featured in an article entitled "Next Stretch for Plastic Electronics" that appeared in Scientific American in 2004. The U.S. Patent office issued a patent protecting PEDOT-TMA on April 22, 2008.
In chemistry, a metallophilic interaction is defined as a type of non-covalent attraction between heavy metal atoms. The atoms are often within Van der Waals distance of each other and are about as strong as hydrogen bonds. The effect can be intramolecular or intermolecular. Intermolecular metallophilic interactions can lead to formation of supramolecular assemblies whose properties vary with the choice of element and oxidation states of the metal atoms and the attachment of various ligands to them.
Takuzo Aida is a polymer chemist known for his work in the fields of supramolecular chemistry, materials chemistry and polymer chemistry. Aida, who is the Deputy Director for the RIKEN Center for Emergent Matter Science (CEMS) and a Distinguished University Professor at the University of Tokyo, has made pioneering contributions to the initiation, fundamental progress, and conceptual expansion of supramolecular polymerization. Aida has also been a leader and advocate for addressing critical environmental issues caused by plastic waste and microplastics in the oceans, soil, and food supply, through the development of dynamic, responsive, healable, reorganizable, and adaptive supramolecular polymers and related soft materials.
Adsorption of polyelectrolytes on solid substrates is a surface phenomenon where long-chained polymer molecules with charged groups bind to a surface that is charged in the opposite polarity. On the molecular level, the polymers do not actually bond to the surface, but tend to "stick" to the surface via intermolecular forces and the charges created by the dissociation of various side groups of the polymer. Because the polymer molecules are so long, they have a large amount of surface area with which to contact the surface and thus do not desorb as small molecules are likely to do. This means that adsorbed layers of polyelectrolytes form a very durable coating. Due to this important characteristic of polyelectrolyte layers they are used extensively in industry as flocculants, for solubilization, as supersorbers, antistatic agents, as oil recovery aids, as gelling aids in nutrition, additives in concrete, or for blood compatibility enhancement to name a few.
Polyelectrolytes are charged polymers capable of stabilizing colloidal emulsions through electrostatic interactions. Their effectiveness can be dependent on molecular weight, pH, solvent polarity, ionic strength, and the hydrophilic-lipophilic balance (HLB). Stabilized emulsions are useful in many industrial processes, including deflocculation, drug delivery, petroleum waste treatment, and food technology.
A two-dimensional polymer (2DP) is a sheet-like monomolecular macromolecule consisting of laterally connected repeat units with end groups along all edges. This recent definition of 2DP is based on Hermann Staudinger's polymer concept from the 1920s. According to this, covalent long chain molecules ("Makromoleküle") do exist and are composed of a sequence of linearly connected repeat units and end groups at both termini.
Bovine submaxillary mucin (BSM) coatings are a surface treatment provided to biomaterials intended to reduce the growth of disadvantageous bacteria and fungi such as S. epidermidis, E. coli, and Candida albicans. BSM is a substance extracted from the fresh salivary glands of cows. It exhibits unique physical properties, such as high molecular weight and amphiphilicity, that allow it to be used for many biomedical applications.
Self-healing hydrogels are a specialized type of polymer hydrogel. A hydrogel is a macromolecular polymer gel constructed of a network of crosslinked polymer chains. Hydrogels are synthesized from hydrophilic monomers by either chain or step growth, along with a functional crosslinker to promote network formation. A net-like structure along with void imperfections enhance the hydrogel's ability to absorb large amounts of water via hydrogen bonding. As a result, hydrogels, self-healing alike, develop characteristic firm yet elastic mechanical properties. Self-healing refers to the spontaneous formation of new bonds when old bonds are broken within a material. The structure of the hydrogel along with electrostatic attraction forces drive new bond formation through reconstructive covalent dangling side chain or non-covalent hydrogen bonding. These flesh-like properties have motivated the research and development of self-healing hydrogels in fields such as reconstructive tissue engineering as scaffolding, as well as use in passive and preventive applications.
In materials science, the term single-layer materials or 2D materials refers to crystalline solids consisting of a single layer of atoms. These materials are promising for some applications but remain the focus of research. Single-layer materials derived from single elements generally carry the -ene suffix in their names, e.g. graphene. Single-layer materials that are compounds of two or more elements have -ane or -ide suffixes. 2D materials can generally be categorized as either 2D allotropes of various elements or as compounds.
Titanium butoxide is a metal alkoxide with the formula Ti(OBu)4 (Bu = –CH2CH2CH2CH3). It is a colorless odorless liquid, although aged samples are yellowish with a weak alcohol-like odor. It is soluble in many organic solvents. Decomposition in water is not hazardous, and therefore titanium butoxide is often used as a liquid source of titanium dioxide, which allows deposition of TiO2 coatings of various shapes and sizes down to the nanoscale.
Boron nitride nanosheet is a two-dimensional crystalline form of the hexagonal boron nitride (h-BN), which has a thickness of one to few atomic layers. It is similar in geometry as well as physical and thermal properties to its all-carbon analog graphene, but has very different chemical and electronic properties – contrary to the black and highly conducting graphene, BN nanosheets are electrical insulators with a band gap of ~5.9 eV, and therefore appear white in color.
Lianzhou Wang is a Chinese Australian materials scientist and professor in the School of Chemical Engineering at the University of Queensland. He is director of the Nanomaterials Centre (Nanomac) and a senior group member at the Australian Institute for Bioengineering and Nanotechnology at the University of Queensland, as well as a Fellow of the Royal Society of Chemistry.
Hydrogel fiber is a hydrogel made into a fibrous state, where its width is significantly smaller than its length. The hydrogel's specific surface area at fibrous form is larger than that of the bulk hydrogel, and its mechanical properties also changed accordingly. As a result of these changes, hydrogel fiber has a faster matter exchange rate and can be woven into different structures.