Ionic Oligomers Research Articles

Calcium Carbonate as an Ionic Molecular Lock for Ultrastrong Fluorescence of Single Organic Molecules

Locking molecular conformation are widely applied in molecular engineering for improved performance. However, locking via organic functional groups often changes the original molecular properties. Following the rigidity and stability of ionic interaction in ionic compounds, we suggested the use of a molecular‐scale ionic compound, calcium carbonate oligomer, as a robust molecular segment to functionalize organic molecules. The rigid structure of the ionic molecular segments locked the organic molecules, which could remarkably limit the intramolecular motion and intermolecular interactions. This ensured a stable and ultrastrong fluorescence of the single organic molecule while preserving its original maximum emission wavelength. The locking strategy was general and extendable to multiple organic molecules. Additionally, the ultrastrong single‐molecular fluorescence can be maintained in inorganic solids with even higher quantum yields and almost unchanged maximum emission wavelength. The highest quantum yield of the investigated molecules reached 99.9%, superior to all reported organic‒inorganic fluorescent composite under air conditions. This work demonstrates a general strategy to restrict intramolecular motion and intermolecular interactions by using ionic oligomers as molecular locks, providing an alternative method for realizing ultraemissive molecules. This further demonstrates a fascinating example of molecular engineering in the presence of inorganic ionic molecules.

Calcium Carbonate as an Ionic Molecular Lock for Ultrastrong Fluorescence of Single Organic Molecules.

Locking molecular conformation are widely applied in molecular engineering for improved performance. However, locking via organic functional groups often changes the original molecular properties. Following the rigidity and stability of ionic interaction in ionic compounds, we suggested the use of a molecular-scale ionic compound, calcium carbonate oligomer, as a robust molecular segment to functionalize organic molecules. The rigid structure of the ionic molecular segments locked the organic molecules, which could remarkably limit the intramolecular motion and intermolecular interactions. This ensured a stable and ultrastrong fluorescence of the single organic molecule while preserving its original maximum emission wavelength. The locking strategy was general and extendable to multiple organic molecules. Additionally, the ultrastrong single-molecular fluorescence can be maintained in inorganic solids with even higher quantum yields and almost unchanged maximum emission wavelength. The highest quantum yield of the investigated molecules reached 99.9%, superior to all reported organic‒inorganic fluorescent composite under air conditions. This work demonstrates a general strategy to restrict intramolecular motion and intermolecular interactions by using ionic oligomers as molecular locks, providing an alternative method for realizing ultraemissive molecules. This further demonstrates a fascinating example of molecular engineering in the presence of inorganic ionic molecules.

Organic-Inorganic Copolymerization Induced Oriented Crystallization for Robust Lightweight Porous Composite.

Porous composites are important in engineering fields for their lightweight, thermal insulation, and mechanical properties. However, increased porosity commonly decreases the robustness, making a trade-off between mechanics and weight. Optimizing the strength of solid structure is a promising way to co-enhance the robustness and lightweight properties. Here, acrylamide and calcium phosphate ionic oligomers are copolymerized, revealing a pre-interaction of these precursors induced oriented crystallization of inorganic nanostructures during the linear polymerization of acrylamide, leading to the spontaneous formation of a bone-like nanostructure. The resulting solid phase shows enhanced mechanics, surpassing most biological materials. The bone-like nanostructure remains intact despite the introduction of porous structures at higher levels, resulting in a porous composite (P-APC) with high strength (yield strength of 10.5MPa) and lightweight properties (density below 0.22 gcm-3). Notably, the density-strength property surpasses most reported porous materials. Additionally, P-APC shows ultralow thermal conductivity (45 mWm-1k-1) due to its porous structure, making its strength and thermal insulation superior to many reported materials. This work provides a robust, lightweight, and thermal insulating composite for practical application. It emphasizes the advantage of prefunctionalization of ionic oligomers for organic-inorganic copolymerization in creating oriented nanostructure with toughened mechanics, offering an alternative strategy to produce robust lightweight materials.

Crosslinking ionic oligomers sol-gel synthesis of high-surface-area mesoporous magnesium carbonate and its general applicability

Mesoporous magnesium carbonate has been widely used in controlled release of drugs, adsorption or catalysis. In traditional methods, expensive alkoxide or MgO are usually employed as Mg-source to prepare mesoporous magnesium carbonate. Herein, based on the crosslinking property of ionic oligomers, a novel crosslinking ionic oligomer sol-gel method was proposed to prepare high-surface-area mesoporous magnesium carbonate using cheap MgCl2·6H2O and CO2 as material. (MgCO3)n crosslinking oligomer sols was produced based on the H-bond capping effects of ethanol and triethylamine. The evolution mechanism of crosslinking (MgCO3)n oligomer sols to gels was studied by using ATR-FTIR and NMR. The results indicated that with the slow volatilization of ethanol and triethylamine, a part of H-bond disappeared, which initiating the chain growth of (MgCO3)n oligomer molecules, and finally forming a crosslinking network. Combined with a CO2 critical point drying process, amorphous mesoporous magnesium carbonate nanoparticle with high surface area was obtained and characterized using ATR-FTIR, XRD, XPS, nitrogen adsorption/desorption analysis, SEM, TEM and EDS systematically. The specific surface area of magnesium carbonate reached 628 m2 g−1 when the n(TEA)/n(Mg2+) was 40:1. Moreover, the general applicability of this method was verified. Mesoporous sulfate and phosphate were synthesized, which indicating the crosslinking oligomer sol-gel chemistry provided a general strategy for the construction of mesoporous inorganic oxysalt materials. Our work has important guiding significance for the preparation of other mesoporous materials that using cheap inorganic salt as raw material.

Expanding from materials to biology inspired by biomineralization

AbstractBiomineralization is the intricate process by which living organisms orchestrate the formation of organic–inorganic composites by regulating the nucleation, orientation, growth, and assembly of inorganic minerals. As our comprehension of biomineralization principles deepens, novel strategies for fabricating inorganic materials based on these principles have emerged. Researchers can also harness biomineralization strategies to tackle challenges in both materials' science and biomedical fields, demonstrating a thriving research field. This review begins by introducing the concept of biomineralization and subsequently shifts its focus to a recently discovered chemical concept: inorganic ionic oligomers and their cross‐linking. As a novel approach for constructing inorganic materials, the inorganic ionic oligomer‐based strategy finds applications in biomimetic regeneration and repair of hard tissues, such as teeth and bones. Aside from innovative methods for material fabrication, biomineralization has emerged as an alternative method for tackling biomedical challenges by integrating materials with biological organisms, facilitating advancements in biomedical fields. Emerging material‐biological integrators play a critical role in areas like vaccine improvement, cancer therapy, universal blood transfusion, and arthritis treatment. This review highlights the profound impact of biomineralization in the development and design of high‐performance materials that go beyond traditional disciplinary boundaries, potentially promoting breakthroughs in materials science, chemical biology, biomedical, and numerous other domains.

Constructing vacancy-rich metal phosphates by the spatial effect of ionic oligomers for enhanced OER activity

By rationally selecting ionic oligomers as building blocks, sub-nano-sized gaps can be constructed in the solid structure of catalysts. This can overcome the inherent limitations associated with vacancy formation of the traditional nucleation pathway.

High Mechanical Strength Alloy-like Minerals Prepared by Inorganic Ionic Co-cross-linking.

Alloys often combine different metals to generate superior mechanical properties. However, it is challenging to prepare high mechanical strength minerals with similar strategies. Using calcium carbonate (CaC) and calcium phosphate (CaP) as examples, this work synthesizes a group of compounds with the chemical formulas Ca(CO3 )x (PO4 )2(1- x )/3 (0 < x < 1, CaCPs) by cross-linking ionic oligomers. Unlike mixtures, these CaCPs exhibit a single temperature for the phase transition from amorphous to crystallized CaC (calcite) and CaP (hydroxyapatite). By heat-induced synchronous crystallization, dual-phase CaC/CaP with continuous crystallized boundaries are resembled to alloy-like minerals (ALMs). The mechanical properties of the ALMs are adjusted by tailoring their chemical compositions to reach a hardness of 5.6GPa, which exceed those of control calcite and hydroxyapatite samples by 430% and 260%, respectively. This strategy expands the chemical scope of inorganic materials and holds promise for preparing high-performance minerals.

Integration of inorganic ionic oligomers and nanocellulose within PVA networks: A degradable and green nanocomposite with self-healable property and high mechanical strength in a wet state

Preparation of green expandable biodegradable polymer materials with high strength and toughness has always been the goal of researchers. Although the research of biodegradable polymer materials has made some progress in recent years, it is still a huge challenge to prepare biodegradable polymer materials with green expandable technology. In this study, biodegradable polyvinyl alcohol (PVA), inorganic calcium phosphate oligomers (CPO ∼ 1 nm), and TEMPO oxide cellulose nanofibers (TOCN) were used to prepare composite materials through simple and green process. The obtained materials, due to the high density of hydrogen bonds and coordination interaction, are conducive to the preparation of PVA-based plastics with fracture strength ≈176.0 MPa. The breaking strength of PVA-based plastics after soaking in water for 7 days at room temperature is ≈ 16.1 MPa, similar to polyethylene in the dry state. In addition, PVA/TOCN/CPO composites can be processed into products with the required shape.

Vilsmeier Complex Promotes Polycondensation of Imidodisulfuryl Chloride with Diols: Preparation of Ionic Oligomer Electrolytes

We report polycondensation of imidodisulfuryl chloride with diol monomers in the presence of catalysts. The method proceeds via stabilization of imidodisulfuryl chloride by the formation of a complex with N,N-dimethylformamide. This compound is well known as a Vilsmeier complex. The method is versatile and permits the incorporation of alkyl monomers in the oligomer backbone, and a maximum of 17 repeating units is reported. Linear ionic oligomers with protons, lithium ions, and BF4– incorporated into the main chain are successfully produced to fabricate self-standing composite single-ion ionic membranes that exhibited good ionic conductivity and stability at high voltages. Pulsed-field gradient nuclear magnetic resonance (PFG NMR) has been utilized to investigate ion diffusion in membranes.

Inorganic Ionic Oligomers Induced Organic‐Inorganic Synergistic Toughening Enabling Mechanical Robust and Recyclable Nanocomposite Hydrogels

AbstractMechanical robust hydrogels are ideal for applications in energy, environment, biomedicine, and structural engineering materials fields. However, high strength and high toughness are usually in conflict with each other, and simultaneously achieving both of them within a hydrogel has been challenging. Herein an organic‐inorganic synergistic toughening strategy is reported via in‐situ inorganic ionic polymerization of calcium phosphate oligomers within polymer composite networks composed of polyvinyl alcohol chains and aramid nanofibers. The composite hydrogels are provided with a prestress‐induced hierarchically fibrous structure through the assembly, which resulted in the mechanical strength and toughness up to 24.15 ± 1.12 MPa and 15.68 ± 1.78 MJ m−3, respectively, surpassing most toughened hydrogels. Through lamination and crosslinking, bulk hydrogels with controllable mechanical anisotropy and significant energy absorption/dissipation ability are produced. Moreover, the recycling and regeneration of the hydrogels are easily realized owing to the physically crosslinked network and acid‐induced dissolution of the inorganic units of the hydrogels, which lays a foundation for the sustainable large‐scale production and application of the hydrogels. This study provides an alternative approach for the development of mechanical robust and recyclable nanocomposite hydrogels for various applications including soft body armor, flexible electronics, soft robotics, etc.

In Situ Biomimetic Mineralization of Bone-Like Hydroxyapatite in Hydrogel for the Acceleration of Bone Regeneration

A critical-sized bone defect, which cannot be repaired through self-healing, is a major challenge in clinical therapeutics. The combination of biomimetic hydrogels and nano-hydroxyapatite (nano-HAP) is a promising way to solve this problem by constructing an osteogenic microenvironment. However, it is challenging to generate nano-HAP with a similar morphology and structure to that of natural bone, which limits the improvement of bone regeneration hydrogels. Inspired by our previous works on organic-inorganic cocross-linking, here, we built a strong organic-inorganic interaction by cross-linking periosteum-decellularized extracellular matrix and calcium phosphate oligomers, which ensured the in situ mineralization of bone-like nano-HAP in hydrogels. The resulting biomimetic osteogenic hydrogel (BOH) promotes bone mineralization, construction of immune microenvironment, and angiogenesis improvement in vitro. The BOH exhibited acceleration of osteogenesis in vivo, achieving large-sized bone defect regeneration and remodeling within 8 weeks, which is superior to many previously reported hydrogels. This study demonstrates the important role of bone-like nano-HAP in osteogenesis, which deepens the understanding of the design of biomaterials for hard tissue repair. The in situ mineralization of bone-like nano-HAP emphasizes the advantages of inorganic ionic oligomers in the construction of organic-inorganic interaction, which provides an alternative method for the preparation of advanced biomimetic materials.

A Bioinspired Ultratough Composite Produced by Integration of Inorganic Ionic Oligomers within Polymer Networks.

The nacre-inspired laminates are promising materials for their excellent mechanics. However, the interfacial defects between organic-inorganic phases commonly lead to the crack propagation and fracture failure of these materials under stress. A natural biomineral, bone, has much higher bending toughness than the nacre. The small size of inorganic building units in bone improves the organic-inorganic interaction, which optimizes the material toughness. Inspired by these biological structures, here, an ultratough nanocomposite laminate is prepared by the integration of ultrasmall calcium phosphate oligomers (CPO, 1 nm in diameter) within poly(vinyl alcohol) (PVA) and sodium alginate (Alg) networks through a simple three-step strategy. Owing to the small size of inorganic building units, strong multiple molecular interactions within integrated organic-inorganic hierarchical structure are built. The resulting laminates exhibit ultrahigh bending strain (>50% without fracture) and toughness (21.5-31.0 MJ m-3), which surpass natural nacre and almost all of the synthetic laminate materials that have been reported so far. Moreover, the mechanics of this laminate is tunable by changing the water content within the bulk structure. This work provides a way for the development of organic-inorganic nanocomposites with ultrahigh bending toughness by using inorganic ionic oligomers, which can be useful in the fields of tough protective materials and energy absorbing materials.

Metal-Ion Oligomerization Inside Electrified Carbon Micropores and its Effect on Capacitive Charge Storage.

Ion adsorption inside electrified carbon micropores is pivotal for the operation of supercapacitors. Depending on the electrolyte, two main mechanisms have been identified so far, the desolvation of ions in solvents and the formation of superionic states in ionic liquids. Here, it is shown that upon confinement inside negatively charged micropores, transition-metal cations dissolved in water associate to form oligomer species. They are identified using in situ X-ray absorption spectroscopy. The cations associate one with each other via hydroxo bridging, forming ionic oligomers under the synergic effect of spatial confinement and Coulombic screening. The oligomers display sluggish dissociation kinetics and accumulate upon cycling, which leads to supercapacitor capacitance fading. They may be dissolved by applying a positive potential, so an intermittent reverse cycling strategy is proposed to periodically evacuate micropores and revivify the capacitance. These results reveal new insights into ion adsorption and structural evolution with their effects on the electrochemical performance, providing guidelines for designing advanced supercapacitors.

Ion Pairing Mediates Molecular Organization Across Liquid/Liquid Interfaces.

Liquid/liquid interfaces play a central role in scientific fields ranging from nanomaterial synthesis and soft matter electronics to nuclear waste remediation and chemical separations. This diversity of functions arises from an interface's ability to respond to changing conditions in its neighboring bulk phases. Understanding what drives this interfacial flexibility can provide novel avenues for designing new functional interfaces. However, limiting this progress is an inadequate understanding of the subtle intermolecular and interphase interactions taking place at the molecular level. Here, we use surface-specific vibrational sum frequency generation spectroscopy combined with atomistic molecular dynamics simulations to investigate the self-assembly and structure of model ionic oligomers consisting of an oligodimethylsiloxane (ODMS) tail covalently attached to a positively charged methyl imidazolium (MIM+) head group at buried oil/aqueous interfaces. We show how the presence of seemingly innocuous salts can impart dramatic changes to the ODMS tail conformations in the oil phase via specific ion effects and ion-pairing interactions taking place in the aqueous phase. These specific ion interactions are shown to drive enhanced amphiphile adsorption, induce morphological changes, and disrupt emergent hydrogen-bonding structures at the interface. Tuning these interactions allows for independent control over the oligomer structure in the oil phase versus interfacial population changes and represents key mechanistic insight that is needed to control chemical reactions at liquid/liquid interfaces.

Biomineralization: Biomimetic Synthesis of Materials and Biomimetic Regulation of Organisms

AbstractThe review summaries our achievements in biomineralization. A new understanding of non‐classical nucleation is introduced, which highlights the formation of ionic clusters during the early mineral formation. This discovery directs to a new chemical concept of inorganic ionic oligomers and their crosslinking. Different from the conventional syntheses of inorganic materials, the inorganic ionic oligomers can be used as the conformable precursors to achieve moldable constructions, which arises from a fusion of classic inorganic and polymer chemistry by sharing the same process for the manufacture of materials. By using the inorganic oligomers, the biomimetic regenerations/ repairs of hard tissues such as tooth enamel and bone can be realized. And the advanced artificial materials superior over biological ones can be developed by inorganic‐organic co‐polymerization. Moreover, biomineralization is a tool for the integration of materials and biological organism. Our attempts demonstrate that the rationally designed materials‐biologicals can contribute to vaccine improvement, universal blood transfusion, and cancer treatment, etc. They follow a transformation of biomineralization study from biomimetic synthesis of materials to biomimetic modification of organisms and furthermore, start an understanding of chemical biological regulation by materials. What is the most favorite and original chemistry developed in your research group?The discovery of ionic oligomers and their crosslinking following a new concept of inorganic ionic polymerization.How do you get into this specific field? Could you please share some experiences with our readers?I got into the field of biomineralization when I was a graduate student. A challenge in biomineralization community is how we can achieve a moldable construction of inorganic materials (biominerals). Fortunately, we observed the formation of ultrasmall ion aggregates at the early nucleation strategy. This finding subsequently directed to our exploration of ionic oligomers and the most important key was a new start of this inorganic study upon a view of polymer chemistry.How do you supervise your students?I keep on asking my students two questions: 1) What unsolvable problem can you solve for our society by your study? 2) What new understanding can you contribute to our scientific community by yourstudy?What is the most important personality for scientific research?Ready to accept challenge, persist and never give up.What are your hobbies? What's your favorite book(s)?I like travel since I can feel different culture and learn many different ideas in the travelling. I prefer history books since I can “earn” much valuable experience in the reading.How do you keep balance between research and family?Working effectively in weekday and relaxing completely in weekend.Who influences you mostly in your life?The group of my friends and colleagues. I learn lots to improve myself under their help and criticisms.Could you please give us some advices on improving Chinese Journal of Chemistry?To induce the best chemical research in China, beginning from review papers but finally moving to the top research papers.

A Highly Sensitive, Reversible, and Bidirectional Humidity Actuator by Calcium Carbonate Ionic Oligomers Incorporated Poly(Vinylidene Fluoride)

AbstractSensitivity and multi‐directional motivation are major two factors for developing optimized humidity‐response materials, which are promising for sensing, energy production, etc. Organic functional groups are commonly used as the water sensitive units through hydrogen bond interactions with water molecules in actuators. The multi‐coordination ability of inorganic ions implies that the inorganic ionic compounds are potentially superior water sensitive units. However, the particle forms of inorganic ionic compounds produced by classical nucleation limit the number of exposed ions to interact with water. Recent progress on the inorganic ionic oligomers has broken through the limitation of classical nucleation, and realized the molecular‐scaled incorporation of inorganic ionic compounds into an organic matrix. Here, the incorporation of hydrophilic calcium carbonate ionic oligomers into hydrophobic poly(vinylidene fluoride) (PVDF) is demonstrated. The ultra‐small calcium carbonate oligomers within a PVDF film endow it with an ultra‐sensitive, reversible, and bidirectional response. The motivation ability is superior to other bidirectional humidity‐actuators at present, which realizes self‐motivation on an ice surface, converting the chemical potential energy of the humidity gradient from ice to kinetic energy.

Water-Salt Oligomers Enable Supersoluble Electrolytes for High-Performance Aqueous Batteries.

Aqueous rechargeable batteries are highly safe, low-cost, and environmentally friendly, but restricted by low energy density. One of the most efficient solutions is to improve the concentration of the aqueous electrolytes. However, each salt is limited by its physical solubility, generally below 21-32molkg-1 (m). Here, a ZnCl2 /ZnBr2 /Zn(OAc)2 aqueous electrolyte with a record super-solubility up to 75 m is reported, which breaks through the physical solubility limit. This is attributed to the formation of acetate-capped water-salt oligomers bridged by Br- /Cl- -H and Br- /Cl- /O-Zn2+ interactions. Mass spectrometry indicates that acetate anions containing nonpolarized protons prohibit the overgrowth and precipitation of ionic oligomers. The polymer-like glass transition temperature of such inorganic electrolytes is found at ≈-70 to -60°C, without the observation of peaks for salt-crystallization and water-freezing from 40 to -80°C. This supersoluble electrolyte enables high-performance aqueous dual-ion batteries that exhibit a reversible capacity of 605.7mAhg-1 , corresponding to an energy density of 908.5Whkg-1 , with a coulombic efficiency of 98.07%. In situ X-ray diffraction and Raman technologies reveal that such high ionic concentrations of the supersoluble electrolyte enable a stage-1 intercalation of bromine into macroscopically assembled graphene cathode.

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.

Crosslinking ionic oligomers as conformable precursors to calcium carbonate.

Inorganic materials have essential roles in society, including in building construction, optical devices, mechanical engineering and as biomaterials1-4. However, the manufacture of inorganic materials is limited by classical crystallization5, which often produces powders rather than monoliths with continuous structures. Several precursors that enable non-classical crystallization-such as pre-nucleation clusters6-8, dense liquid droplets9,10, polymer-induced liquid precursor phases11-13 and nanoparticles14-have been proposed to improve the construction of inorganic materials, but the large-scale application of these precursors in monolith preparations is limited by availability and by practical considerations. Inspired by the processability of polymeric materials that can be manufactured by crosslinking monomers or oligomers15, here we demonstrate the construction of continuously structured inorganic materials by crosslinking ionic oligomers. Using calcium carbonate as a model, we obtain a large quantity of its oligomers (CaCO3)n with controllable molecular weights, in which triethylamine acts as a capping agent to stabilize the oligomers. The removal of triethylamine initiates crosslinking of the (CaCO3)n oligomers, and thus the rapid construction of pure monolithic calcium carbonate and even single crystals with a continuous internal structure. The fluid-like behaviour of the oligomer precursor enables it to be readily processed or moulded into shapes, even for materials with structural complexity and variable morphologies. The material construction strategy that we introduce here arises from a fusion of classic inorganic and polymer chemistry, and uses the same cross-linking process for the manufacture the materials.

The pathway and kinetics of hierarchical assembly of ionic oligomers into a lyotropic columnar phase.

Ionic benzene-1,3,5-tricarboxamide (BTA) molecules can self-assemble into hollow cylinders which further arrange into columnar phases in water. In situ investigations suggest a multi-step pathway of supramolecular assembly via formation of dispersed molecular aggregates followed by a less ordered intermediate phase before the equilibrium columnar phase is formed. The pathway and kinetics of the formation of lyotropic LC phases through hierarchical supramolecular assembly are similar to non-classical crystallization, in line with an emerging holistic view on crystallization and self-assembly.