Search Results (119)

Experimental research in the field of science and technology of polymeric materials and their hybrid organic-inorganic systems has been and will continue to be based on the execution of tests to establish robust structure-morphology-property-processing correlations. Although absolutely necessary, these tests are often time-consuming and require specific efforts; sometimes, they must be repeated to achieve a certain reproducibility and reliability. In this context, the introduction of methods like the Design of Experiments (DoEs) has made it possible to drastically reduce the number of experimental tests required for a complete characterization of a material system. However, this does not seem enough. Indeed, further improvements are being observed thanks to the introduction of a very recent approach based on the use of artificial intelligence (AI) through the exploitation of a “machine learning (ML)” strategy: this way, it is possible to “teach” AI how to use literature data already available (and even incomplete) for material systems similar to the one being explored to predict key parameters of this latter, minimizing the error while maximizing the reliability. This work aims to provide an overview of the current, new (and up-to-date) use of AI/ML strategies in the field of sol-gel-derived hybrid materials. Full article

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the in situ hydrolysis–condensation of triethoxy(octyl)silane (OS) in an amino-terminated polydimethylsiloxane (APT-PDMS) aqueous dispersion was investigated. The sol was applied to plain-weave cotton and polyester by a pad-dry-cure process and benchmarked against a commercial fluorinated finish. Morphology and chemistry were characterised by SEM–EDS, ATR-FTIR, and Raman spectroscopy; wettability was assessed by static contact angle, ISO 4920 spray ratings, and AATCC 193 water/alcohol repellence; and durability, handle, and breathability were evaluated through repeated laundering, bending stiffness, and water-vapour transmission rate measurements. The silica/PDMS coating formed a uniform, strongly adherent nanostructured layer conferring static contact angles of 130° on cotton and 145° on polyester. After five ISO 105-C10 wash cycles, the treated fabrics still displayed a spray rating of 5/5 and AATCC 193 grade 7, outperforming or equalling the fluorinated control, while causing ≤5% loss of water-vapour permeability and only a marginal increase in bending stiffness. These results demonstrate that the proposed one-step, water-borne sol–gel process affords a sustainable, industrially scalable route to high-performance, durable, water-repellent finishes for both natural and synthetic textiles, offering a viable alternative to PFAS-based chemistry for outdoor apparel and technical applications. Full article

Combining the properties of organic and inorganic components with high surface areas and large pore volumes opens up countless possibilities for designing materials tailored to a wide range of advanced applications. As the majority of mesoporous hybrid materials are siliceous, the development of cost-effective synthetic approaches to produce water-stable hybrids with controlled porosity and functionality remains essential. Herein, we describe an original strategy for the synthesis of bridged mesoporous titania–bisphosphonate hybrids based on a one-step, template-free, non-hydrolytic sol–gel process. The reaction between Ti(OiPr)₄ and several flexible or rigid bisphosphonate esters, in the presence of acetic anhydride (Ac₂O) leads to the formation of TiO₂ anatase nanorods interconnected by fully condensed bisphosphonate groups. The general method that we depict is quantitative and low cost. All materials are mesoporous with very high specific surface areas (up to 520 m²·g⁻¹) and pore volumes (up to 0.93 cm³·g⁻¹). Full article

In the field of enhanced oil recovery (EOR), particularly for water control in high-temperature reservoirs, there is a critical need for effective in-depth water shutoff and conformance control technologies. Polymer-based in situ-cross-linked gels are extensively employed for enhanced oil recovery (EOR), yet their short gelation time under high-temperature reservoir conditions (e.g., >120 °C) limits effective in-depth water shutoff and conformance control. To address this, we developed a hydrogel system via the in situ cross-linking of polyacrylamide (PAM) with phenolic resin (PR), reinforced by silica sol (SS) nanoparticles. We employed a variety of research methods, including bottle tests, viscosity and rheology measurements, scanning electron microscopy (SEM) scanning, density functional theory (DFT) calculations, differential scanning calorimetry (DSC) measurements, quartz crystal microbalance with dissipation (QCM-D) measurement, contact angle (CA) measurement, injectivity and temporary plugging performance evaluations, etc. The composite gel exhibits an exceptional gelation period of 72 h at 130 °C, surpassing conventional systems by more than 4.5 times in terms of duration. The gelation rate remains almost unchanged with the introduction of SS, due to the highly pre-dispersed silica nanoparticles that provide exceptional colloidal stability and the system’s pH changing slightly throughout the gelation process. DFT and SEM results reveal that synergistic interactions between organic (PAM-PR networks) and inorganic (SS) components create a stacked hybrid network, enhancing both mechanical strength and thermal stability. A core flooding experiment demonstrates that the gel system achieves 92.4% plugging efficiency. The tailored nanocomposite allows for the precise management of gelation kinetics and microstructure formation, effectively addressing water control and enhancing the plugging effect in high-temperature reservoirs. These findings advance the mechanistic understanding of organic–inorganic hybrid gel systems and provide a framework for developing next-generation EOR technologies under extreme reservoir conditions. Full article

Nanotopography refers to the intricate surface characteristics of materials at the sub-micron (<1000 nm) and nanometer (<100 nm) scales. These topographical surface features significantly influence the physical, chemical, and biological properties of biomaterials, affecting their interactions with cells and surrounding tissues. The development of nanostructured surfaces of polymeric nanocomposites has garnered increasing attention in the fields of tissue engineering and regenerative medicine due to their ability to modulate cellular responses and enhance tissue regeneration. Various top-down and bottom-up techniques, including nanolithography, etching, deposition, laser ablation, template-assisted synthesis, and nanografting techniques, are employed to create structured surfaces on biomaterials. Additionally, nanotopographies can be fabricated using polymeric nanocomposites, with or without the integration of organic and inorganic nanomaterials, through advanced methods such as using electrospinning, layer-by-layer (LbL) assembly, sol–gel processing, in situ polymerization, 3D printing, template-assisted methods, and spin coating. The surface topography of polymeric nanocomposite scaffolds can be tailored through the incorporation of organic nanomaterials (e.g., chitosan, dextran, alginate, collagen, polydopamine, cellulose, polypyrrole) and inorganic nanomaterials (e.g., silver, gold, titania, silica, zirconia, iron oxide). The choice of fabrication technique depends on the desired surface features, material properties, and specific biomedical applications. Nanotopographical modifications on biomaterials’ surface play a crucial role in regulating cell behavior, including adhesion, proliferation, differentiation, and migration, which are critical for tissue engineering and repair. For effective tissue regeneration, it is imperative that scaffolds closely mimic the native extracellular matrix (ECM), providing a mechanical framework and topographical cues that replicate matrix elasticity and nanoscale surface features. This ECM biomimicry is vital for responding to biochemical signaling cues, orchestrating cellular functions, metabolic processes, and subsequent tissue organization. The integration of nanotopography within scaffold matrices has emerged as a pivotal regulator in the development of next-generation biomaterials designed to regulate cellular responses for enhanced tissue repair and organization. Additionally, these scaffolds with specific surface topographies, such as grooves (linear channels that guide cell alignment), pillars (protrusions), holes/pits/dots (depressions), fibrous structures (mimicking ECM fibers), and tubular arrays (array of tubular structures), are crucial for regulating cell behavior and promoting tissue repair. This review presents recent advances in the fabrication methodologies used to engineer nanotopographical microenvironments in polymeric nanocomposite tissue scaffolds through the incorporation of nanomaterials and biomolecular functionalization. Furthermore, it discusses how these modifications influence cellular interactions and tissue regeneration. Finally, the review highlights the challenges and future perspectives in nanomaterial-mediated fabrication of nanotopographical polymeric scaffolds for tissue engineering and regenerative medicine. Full article

This work is part of a current and essential issue aiming to find a solution for the replacement of chromium(VI) and cadmium in the surface treatment process applied to electrical connectors. The application of a protective coating obtained by the sol–gel route proves to be an interesting alternative method and numerous studies describe efficient anticorrosion coatings to protect various metallic alloys. The issue of electrical connectors made of 6061 alloy is to combine anticorrosion protection and electrical conduction, which are antagonistic properties, so multifunctional sol–gel coatings and/or architectures have to be synthesized and shaped on connectors. In this work, several experimental parameters, such as the type of carbon filler, the hydrolysis ratio, the precursors’ introduction order are studied and evaluated to achieve industrial requirements. Thus, aqueous suspensions of carbon fillers have been introduced into sol–gel formulations to give rise to conductive coatings (200–500 mΩ_□) with high anticorrosion properties (500 h NSS resistance), in which thickness is less than 10 microns. The incorporation of organic additives poly(2-ethyl-2-oxazoline) or hydroxypropylmethylcellulose positively impacts the flash point of the sol (>60 °C) making the sol–gel process compatible with the HSE recommendation and the ATEX standard. Full article

In this study, novel anion photo-responsive supramolecular hydrogels based on cysteine–silver sol (CSS) and iodate anions (IO₃⁻) were prepared. The peculiarities of the self-assembly process of gel formation in the dark and under visible-light exposure were studied using a complex of modern physico-chemical methods of analysis, including viscosimetry, UV spectroscopy, dynamic light scattering, electrophoretic light scattering, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. In the dark phase, the formation of weak snot-like gels takes place in a quite narrow IO₃⁻ ion concentration range. The visible-light exposure of these gels leads to an increase in their viscosity and dramatic change in their color. The morphology of gels alters after light irradiation that is reflected in the formation of a huge number of spherical/elliptical particles and the thickening of the fibers of the gel network. The interaction of CSS with IO₃⁻ anions has features of a redox process, which leads to the formation of silver iodide/silver oxide nanoparticles inside and on the surface of CSS particles. CSS possesses selectivity only to IO₃⁻ anions compared to many other inorganic ions relevant for humans and the environment. Thus, the CSS/IO₃⁻ system is non-trivial and can be considered as a novel low-molecular-weight gelator with photosensitive properties, as another way to produce silver iodide nanoparticles, and as a new approach for IO₃⁻ ion detection. Full article

The sol–gel process is a green method used in the last few decades to synthesize new organic–inorganic phosphorus-containing hybrid materials. The sol–gel synthesis is a green method because it takes place in mild conditions, mostly by using water or alcohol as solvents, at room temperature. Therefore, the sol–gel method is, among others, a promising route for obtaining metal-phosphonate networks. In addition to phosphorus, the obtained hybrid materials could also contain titanium, zirconium, boron, and other elements, which influence their properties. The sol–gel process has two steps: first, the sol formation, and second, the transition to the gel phase. In other words, the sol–gel process converts the precursors into a colloidal solution (sol), followed by obtaining a network (gel). By using the sol–gel method, different organic moieties could be introduced into an inorganic matrix, resulting in organic–inorganic hybrid structures (sometimes they are also referred as organic–inorganic copolymers). Full article

The development of photo-/electro-chemical and flexible electronics has stimulated research in catalysis, informatics, biomedicine, energy conversion, and storage applications. Gels (e.g., aerogel, hydrogel) comprise a range of polymers with three-dimensional (3D) network structures, where hydrophilic polyacrylamide, polyvinyl alcohol, copolymers, and hydroxides are the most widely studied for hydrogels, whereas 3D graphene, carbon, organic, and inorganic networks are widely studied for aerogels. Encapsulation of functional species with hydrogel building blocks can modify the optoelectronic, physicochemical, and mechanical properties. In addition, aerogels are a set of nanoporous or microporous 3D networks that bridge the macro- and nano-world. Different architectures modulate properties and have been adopted as a backbone substrate, enriching active sites and surface areas for photo-/electro-chemical energy conversion and storage applications. Fabrication via sol–gel processes, module assembly, and template routes have responded to professionalized features and enhanced performance. This review presents the most studied hydrogel materials, the classification of aerogel materials, and their applications in flexible sensors, batteries, supercapacitors, catalysis, biomedical, thermal insulation, etc. Full article

Organic–inorganic hybrid silica materials, incorporating an organic group bridging two silicon atoms, have demonstrated great potential in creating membranes with excellent permselectivity. Yet, the large-scale production of polymer-supported flexible hybrid silica membranes has remained a significant challenge. In this study, we present an easy and scalable approach for fabricating these membranes. By employing a sol–gel ultrasonic spray process with a single-pass method, we deposited a thin and uniform hybrid active layer onto a porous polymer substrate. We first optimized the deposition conditions, including substrate temperature, the binary solvent ratio of the silica sol, and various ultrasonic spray parameters. The resulting flexible hybrid silica membranes exhibited exceptional dehydration performance for isopropanol (IPA)/water solutions (IPA: 90 wt%) in the pervaporation process, achieving a water flux of 0.6 kg/(m² h) and a separation factor of around 1300. This work demonstrates that the single-pass ultrasonic spray method is an effective strategy for the large-scale production of polymer-supported flexible hybrid silica membranes. Full article

Doping inorganic acid ions represents a promising pathway to improving the photocatalytic activity of TiO₂, and oxygen vacancy has been regarded as the determinant factor for photocatalytic activity. A series of samples doped with Cl⁻, NO₃⁻, and SO₄²⁻ was prepared via a simple sol–gel method. Two different oxygen vacancies in the crystal layer of NO₃⁻/TiO₂ and Cl⁻/TiO₂ were found, and those are [Ti³⁺]-V₀-[Ti³⁺] and [Ti³⁺]-Cl, respectively. The photocurrent of NO₃⁻/TiO₂ with [Ti³⁺]-V₀-[Ti³⁺] is significantly greater than that of Cl⁻/TiO₂ with [Ti³⁺]-Cl. The least oxygen vacancy is in the gel layer of SO₄²⁻/TiO₂, and the negligible photocurrent is due to difficulty in forming a stable sol. Furthermore, the process conditions for the application of TiO₂ were investigated in this work. The optimal process parameters are to adjust the solution to pH = 3 during sol–gel preparation, to adopt 550 °C as the calcination temperature, and to use an alkaline electrolyte, while the rest of the preparation conditions remain unchanged. This work reveals a new avenue for designing efficient photocatalysts for air pollutant degradation. Full article

Lead contamination in water poses significant health risks, making its removal imperative. In this study, magnetic strontium ferrite (SrFe₁₂O₁₉) nanoparticles were facilely synthesized by the Pechini sol–gel method and subsequently functionalized with a novel chitosan–Schiff base ligand to obtain a novel inorganic/organic nanocomposite for removing Pb(II) ions from aqueous solutions. The chitosan–Schiff base ligand was synthesized through the reaction of chitosan with 2,4,5-trihydroxybenzaldehyde. The presence of two X-ray diffraction (XRD) peaks at 2Ɵ = 10.5° and 2Ɵ = 20.5°, alongside the characteristic SrFe₁₂O₁₉ peaks, confirmed the functionalization of the nanoparticles with the ligand. Additionally, a significant decrease in the saturation magnetization value from 40.29 emu/g in pure SrFe₁₂O₁₉ nanoparticles to 17.32 emu/g in the nanocomposite further verified the functionalization. The presence of carbon (C) and nitrogen (N) atoms in the energy-dispersive X-ray (EDX) pattern of the nanocomposite, in addition to iron (Fe), strontium (Sr), and oxygen (O), also confirmed the functionalization. The nanocomposite’s maximum adsorption capacity for Pb(II) ions was 390.63 mg/g. Moreover, the adsorption process is endothermic, spontaneous, and chemical, occurring via complexation with -C=N and -OH groups, and it fits well with the Langmuir equilibrium isotherm and the pseudo-second-order kinetic equation. Full article

Cellulose/silica nanocomposites, synthesised through the sol–gel technique, have garnered significant attention for their unique properties and diverse applications. The distinctive characteristics of these nanocomposites are influenced by a range of factors, including the cellulose-to-silica ratio, precursor concentration, pH, catalysts, solvent selection, temperature, processing techniques, and agitation. These variables play a pivotal role in determining the nanocomposites’ structure, morphology, and mechanical properties, facilitating tailoring for specific applications. Studies by Raabe et al. and Barud et al. demonstrated well-deposited silica nanoparticles within the interstitial spaces of cellulosic fibres, achieved through TEOS precursor hydrolysis and the subsequent condensation of hydroxyl groups on the cellulose fibre surface. The introduction of TEOS established a robust affinity between the inorganic filler and the polymer matrix, emphasising the substantial impact of TEOS concentration on the size and morphology of silica nanoparticles in the final composites. The successful functionalisation of cellulose fibres with the TEOS precursor via the sol–gel method was reported, resulting in reduced water uptake and enhanced mechanical strength due to the strong chemical interaction between silica and cellulose. In research conducted by Feng et al., the silica/cellulose composite exhibited reduced weight loss compared to the pristine cellulose matrix, with the integration of silica leading to an elevated temperature of composite degradation. Additionally, Ahmad et al. investigated the effects of silica addition to cellulose acetate (CA) and polyethylene glycol membranes, noting an increase in Young’s modulus, tensile strength, and elongation at break with silica incorporation. However, concentrations exceeding 4% (w/v) resulted in significant phase separations, leading to a decline in mechanical properties. Full article

The need to improve the expectancy and quality of life of subjects affected by disabling pathologies that require the replacement or regeneration of tissues or parts of the body has fueled the development of innovative, better-performing materials that are capable of integrating into and being tolerated by body tissues. Materials with these characteristics, i.e., bio-functionality, bio-safety, and biocompatibility, are defined as biomaterials. One of the many methods for producing such materials is the sol–gel technique. This process is mainly used for the preparation of ceramic oxides at low temperatures, through hydrolysis and polycondensation reactions of organometallic compounds within a hydroalcoholic solution. This study is based on a specific type of biomaterial: organic–inorganic hybrids. The aim of this study is to provide an overview of the advantages and disadvantages of the sol–gel technique, as well as describe the preparation and chemical and biological characterization, uses, and future prospects of these biomaterials. In particular, the use of plant drugs as organic components of the hybrid material is the innovation of this manuscript. The biological properties of plant extracts are numerous, and for this reason, they deserve great attention from the scientific community. Full article

Organic–inorganic hybrid dielectric nanomaterials are vital for OTFT applications due to their unique combination of organic dielectric and inorganic properties. Despite the challenges in preparing stable titania (TiO₂) nanoparticles, we successfully synthesized colloidally stable organic–inorganic (O-I) TiO₂ hybrid nanoparticles using an amphiphilic polymer as a stabilizer through a low-temperature sol–gel process. The resulting O-I TiO₂ hybrid sols exhibited long-term stability and formed a high-quality dielectric layer with a high dielectric constant (κ) and minimal leakage current density. We also addressed the effect of the ethylene oxide chain within the hydrophilic segment of the amphiphilic polymer on the dielectric properties of the coating film derived from O-I TiO₂ hybrid sols. Using the O-I TiO₂ hybrid dielectric layer with excellent insulating properties enhanced the electrical performance of the gate dielectrics, including superior field-effect mobility and stable operation in OTFT devices. We believe that this study provides a reliable method for the preparation of O-I hybrid TiO₂ dielectric materials designed to enhance the operational stability and electrical performance of OTFTs. Full article