Organic Hybrid Polymer Research Articles

Sulfur-Based Building Blocks in BN- and BO-Doped Inorganic–Organic Hybrid Polymers

Sulfur-Based Building Blocks in BN- and BO-Doped Inorganic–Organic Hybrid Polymers

Front Cover: 1,2,5‐Azadiborolane as a Building Block for Inorganic–Organic Hybrid Polymers (Eur. J. Inorg. Chem. 3/2024)

Front Cover: 1,2,5‐Azadiborolane as a Building Block for Inorganic–Organic Hybrid Polymers (Eur. J. Inorg. Chem. 3/2024)

Enhancing fracture toughness of polydimethylsiloxane with cyclosiloxane hybrid polymer microspheres

Polydimethylsiloxane (PDMS) offers many unique advantages, but the poor fracture toughness (300–500 J/m2) limits its applications. Conventional methods of toughening PDMS through chain modification or inorganic fillers may negatively impact other properties, such as increase in hysteresis, stiffness, or viscosity. To address this problem, we introduce organic cyclosiloxane hybrid polymer (CHP) microspheres to toughen PDMS. These microspheres are synthesized by emulsion polymerization of two cyclosiloxane monomers and can be regarded as an extremely crosslinked PDMS. The interpenetration of polymer chains between CHP and matrix increases the interface adhesion to transfer the stress while the high modulus contrast can prevent the propagation of cracks, resulting in a high toughness without a sharp increase in stiffness. At the same time, the low friction between the filler and matrix reduces viscosity and hysteresis. Moreover, by incorporating magnetically responsive Fe3O4 nanoparticles, the CHP microspheres can be aligned. Aligned-CHP/PDMS composites exhibit a fracture toughness of 4223 J/m2, three times higher than SiO2 reinforced composites and nearly an order of magnitude higher than pure PDMS. These composites also have a lower modulus (3.3 MPa), lower hysteresis (0.167), and a viscosity two orders of magnitude lower compared to SiO2-filled counterparts. This method offers a new pathway for toughening siloxane elastomers without affecting other properties.

1,2,5‐Azadiborolane as a Building Block for Inorganic–Organic Hybrid Polymers

AbstractThe incorporation of BN units in organic scaffolds by isoelectronic/isosteric substitution of selected CC couples has emerged as an efficient tool to produce new materials with useful properties and functions. The knowledge about BN‐doped inorganic–organic hybrid polymers, however, is still rather scarce. This is especially true for linear or cyclolinear macromolecules that feature longer inorganic chains. Herein, we introduce 1,2,5‐azadiborolane as a polymer building block for the first time. An attempt to apply it for the synthesis of a cyclolinear poly(iminoborane) resulted after only two B−N coupling events in the formation of a molecular compound comprising a chain of three nitrogen and two boron atoms – as confirmed by single‐crystal X‐ray diffractometry. In combination with a p‐phenylene diamine‐based co‐monomer, we accomplished to incorporate the 1,2,5‐azadiborolane into a hybrid polymer of considerable molecular weight that features a B2N3 chain. We additionally synthesized a small molecular model compound for the polymer and characterized it crystallographically as well. Comparison of the UV‐vis spectra of the monomer, the oligomer, and the polymer revealed systematic red‐shifts of the longest‐wavelength absorption band with increasing number of BN units in the chain.

A Brief Overview of the Microstructural Engineering of Inorganic-Organic Composite Membranes Derived from Organic Chelating Ligands.

This review presents a concise conceptual overview of membranes derived from organic chelating ligands as studied in several works. The authors' approach is from the viewpoint of the classification of membranes by matrix composition. The first part presents composite matrix membranes as a key class of membranes and makes a case for the importance of organic chelating ligands in the formation of inorganic-organic composites. Organic chelating ligands, categorized into network-modifying and network-forming types, are explored in detail in the second part. Four key structural elements, of which organic chelating ligands (as organic modifiers) are one and which also include siloxane networks, transition-metal oxide networks and the polymerization/crosslinking of organic modifiers, form the building blocks of organic chelating ligand-derived inorganic-organic composites. Three and four parts explore microstructural engineering in membranes derived from network-modifying and network-forming ligands, respectively. The final part reviews robust carbon-ceramic composite membranes as important derivatives of inorganic-organic hybrid polymers for selective gas separation under hydrothermal conditions when the proper organic chelating ligand and crosslinking conditions are chosen. This review can serve as inspiration for taking advantage of the wide range of possibilities presented by organic chelating ligands.

UV-Activated, Transparent Oxygen Scavenger Coating Based on Inorganic–Organic Hybrid Polymer (ORMOCER®) with High Oxygen Absorption Capacity

Oxygen scavengers are used to reduce the oxygen permeation of packaging (active barrier) and to absorb oxygen from its direct environment, e.g., a headspace of packaged food. Few oxygen scavenger coatings have been developed. Therefore, in this study, a novel oxygen scavenger coating has been developed. It is based on inorganic–organic polymers (ORMOCER®). The oxygen absorption reaction is activated by UV light. The scavenger was synthesized, coated on aluminum foil, subsequently dried and afterwards laminated with a polyethylene sealing layer. UV light activates the oxygen scavenging reaction. The oxygen absorption capacity, measured at 23 °C and 0% r.h., was 242 ± 8 mg oxygen/g scavenger coating. When the oxygen scavenger coating layer was laminated by using a two-component polyurethane laminating adhesive, the absorption capacity was hardly reduced, with a measured absorption capacity of 223 ± 18 mg oxygen/g scavenger coating. In an experimental packaging sample with the oxygen scavenger coating with a thickness (dry) of 3 µm and 18 µm, near-zero mbar oxygen partial pressure was reached by the non-laminated oxygen scavenger coatings within two days, and within about 20 days when laminated with a polyurethane laminating adhesive and a PE-layer on the oxygen scavenger layer. The oxygen partial pressure was kept near zero mbar for 500 days, whereas in the experimental packaging without oxygen scavenger, the oxygen partial pressure increased to 110 mbar during this time. The developed oxygen scavenger based on inorganic–organic polymers can be applied as wet chemical coating on various surfaces with standard application procedures. Application scenarios are oxygen-sensitive goods such as food, pharmaceutical products and cosmetics.

Engineering the Charge Density on an In2.77S4/Porous Organic Polymer Hybrid Photocatalyst for CO2-to-Ethylene Conversion Reaction

The development of an efficient photocatalyst for C2 product formation from CO2 is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In2.77S4 and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C2H4, with a formation rate of 67.65 μmol g-1 h-1. Two different oxidation states of the In2.77S4 spinel were exploited for the C-C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated via several photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C2H4 formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.

An eight‐membered cyclosiloxane conjugated microporous polymer performed a rapid and sensitive fluorescence detection of 2,4‐dinitrophenol

AbstractA nitrogen‐rich porous inorganic–organic hybrid polymer, TMPS, was successfully synthesized by Friedel–Crafts arylation with anhydrous aluminum trichloride as a catalyst, which has good sensitivity to nitro‐aromatic compounds. The material was systematically characterized by using FT‐IR, solid‐state 13C NMR, elemental analysis, powder X‐ray diffraction, solid‐state UV–Vis, and so forth. The thermogravimetric analysis experiments confirmed that TMPS has very good thermal stability. Its Brunauer Emmett Teller specific surface area measured by nitrogen adsorption desorption experiment is 115 m2 g−1. Due to its excellent conjugated structure and nitrogen‐rich features, TMPS exhibits a very high sensitivity and selectivity to 2,4‐dinnitrophenol. Based on the data obtained from the fluorescence detection experiment, the KSV and limit of detection are 1.84 × 104 L mol−1 and 1.63 × 10−11 mol L−1, respectively. Therefore, TMPS can act as a fast and sensitive fluorescent sensor to detect DNP.

A Self‐Assembly Method for Tunable and Scalable Nano‐Stamps: A Versatile Approach for Imprinting Nanostructures

AbstractIn nanoimprint lithography (NIL), the imprinting stamp's fabrication is still a significant cost factor among the consumables. Bottom‐up lithography approaches based on a phase‐separation of polymer blends can provide a cost‐effective route for fabricating these stamps. Today's polymers used to prepare phase‐separated nanostructures (PSN), however, exhibit low glass transition temperatures. As a result, the PSN are prone to in‐plane stamp distortions in the presence of high imprinting pressure and temperature, limiting their practical relevance for NIL. Here, the realization of mechanically and thermally stable PSN‐based imprinting stamps for NIL systems via a phase‐separation of a homopolymer/inorganic–organic hybrid polymer blend is reported. It is demonstrated that these imprinting stamps are easily tunable and scalable by adjusting the formulation of homopolymer/hybrid polymer mixture and deposition conditions. Feature sizes in PSN ranging from a few μm down to 100 nm are achieved through an interplay of these factors. As demonstrations of the envisioned applications, the developed imprinting stamps are integrated into a roll‐to‐roll NIL system for patterning a polystyrene thin‐film. Moreover, light management is demonstrated by nanopatterning of a perovskite semiconductor in plate‐to‐plate process. The nanopatterned perovskite film achieves an integrated absorption and a photoluminescence emission peak increase of 7%rel and 121%rel, respectively.

Molecular motor-driven filament transport across three-dimensional, polymeric micro-junctions

Molecular motor-driven filament systems have been extensively explored for biomedical and nanotechnological applications such as lab-on-chip molecular detection or network-based biocomputation. In these applications, filament transport conventionally occurs in two dimensions (2D), often guided along open, topographically and/or chemically structured channels which are coated by molecular motors. However, at crossing points of different channels the filament direction is less well determined and, though crucial to many applications, reliable guiding across the junction can often not be guaranteed. We here present a three-dimensional (3D) approach that eliminates the possibility for filaments to take wrong turns at junctions by spatially separating the channels crossing each other. Specifically, 3D junctions with tunnels and overpasses were manufactured on glass substrates by two-photon polymerization, a 3D fabrication technology where a tightly focused, femtosecond-pulsed laser is scanned in a layer-to-layer fashion across a photo-polymerizable inorganic–organic hybrid polymer (ORMOCER®) with µm resolution. Solidification of the polymer was confined to the focal volume, enabling the manufacturing of arbitrary 3D microstructures according to computer-aided design data. Successful realization of the 3D junction design was verified by optical and electron microscopy. Most importantly, we demonstrated the reliable transport of filaments, namely microtubules propelled by kinesin-1 motors, across these 3D junctions without junction errors. Our results open up new possibilities for 3D functional elements in biomolecular transport systems, in particular their implementation in biocomputational networks.

Facile synthesis of inorganic–organic hybrid fluorescent nanoparticles with AIE feature using hexachlorocyclotriphosphazene as the bridge

In recent 20 years, the functional materials with aggregation-induced emission (AIE) feature have shown huge superiority and great potential in biomedicine field and numerous strategies have been developed to fabricate these AIE-active functional materials. Though delightful developments, facile synthesis of inorganic–organic hybrid fluorescent nanoparticles with AIE feature has seldom reported thus far. In this work, we reported for the first time that novel cross-linked inorganic–organic hybrid polyphosphazene nanospheres with AIE feature could be simply synthesized via conjugation AIE-active fluorophore tetraphenylethylene derivative (TPE-NH2) with hydrophilic polyethylene glycol (PEG-NH2) using hexachlorocyclotriphosphazene (HCCP) as the bridge. This strategy is simple and high-efficient with some advantages (e.g., the reaction can occur under room temperature, the reaction time is short, no surfactant is required and no air-protection is needed). The structure, morphology and spectroscopic properties of TPE-HCCP-PEG nanoparticles (NPs) were characterized by various apparatus. To further evaluate their potential applications in biomedical fields, biocompatibility and cell uptake behavior of TPE-HCCP-PEG composites have been examined. Results demonstrated that TPE-HCCP-PEG NPs possessed intensive fluorescence and high water dispersibility and were of low cytotoxicity. These features endow TPE-HCCP-PEG NPs huge potential in fluorescence imaging. Also, the strategy can be extended for the construction of many other inorganic–organic hybrid polymers taken advantage of their unique features and convenient synthetic method. We expect that this work will open a new avenue for the synthesis of inorganic heterocycles centered AIE-active materials with extensive application prospects.

Synthesis of Inorganic–Organic Hybrid Polymers

Key words hypercross-linked polymers - inorganic–organic hybrid polymer synthesis - Friedel–Crafts reaction

An Inorganic–Organic Hybrid Polymer Cocatalyst for Photoelectrochemical Water Oxidation with Dual Functions of Accelerating Kinetics and Improving Charge Transfer

Oxygen evolution cocatalysts (OECs) play important roles in improving the efficiency of photocatalysts in solar water splitting. Inorganic–organic hybrid polymers (IOHPs), which have good electroly...

Multifunctional materials for lean processing of waferscale optics

AbstractThe continuous miniaturization of components and devices along with the increasing need of sustainability in production requires materials which can fulfill the manifold requests concerning their functionality. From an industrial point of view emphasis is on cost reduction either for the materials, the processes, or for both, along with a facilitation of processing and a general reduction of resource consumption in manufacturing. Multifunctional nanoscale materials have been widely investigated due to their tunable material properties and their ability to fulfill the increasingly growing demands in miniaturization, ease of processes, low-cost manufacturing, scalability, reliability, and finally sustainability. A material class which fulfills these requirements and is suited for integrated or waferscale optics are inorganic–organic hybrid polymers such as ORMOCER®s [ORMOCER®is registered by the Fraunhofer Gesellschaft für Angewandte Forschung e.V. and commercialized by microresist technology GmbH under license since 2003]. The combination of chemically designed multifunctional low-cost materials with tunable optical properties is very attractive for (integrated) optical and waferscale applications via a variety of different nano- and microstructuring techniques to fabricate micro- and nano-optical components, typically within less than a handful of process steps. The influence of photoinitiator and cross-linking conditions onto the optical properties of an acrylate-based inorganic–organic hybrid polymer will be discussed, and its suitability for being applied in waferscale optics is demonstrated and discussed for miniaturized multi- and single channel imaging optics.

Correction: Strongly coupled Mn3O4-porous organic polymer hybrid: a robust, durable and potential nanocatalyst for alcohol oxidation reactions

Correction for ‘Strongly coupled Mn3O4-porous organic polymer hybrid: a robust, durable and potential nanocatalyst for alcohol oxidation reactions’ by Karnekanti Dhanalaxmi et al., RSC Adv., 2016, 6, 36728–36735, DOI: 10.1039/C6RA07200C.

Structure and tuneable luminescence in polymeric zinc compounds based on 3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

Inorganic–organic hybrid polymers based on 3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4-Hbpt) ligand were synthesized and subsequently characterized by single-crystal X-ray diffraction, FT–IR spectra, elemental analyses, thermogravimetric (TG) analyses and PXRD. The X-ray diffraction analyses revealed that the complexes [Zn(3,4-Hbpt)Cl2] and [Zn(3,4-Hbpt)Br2] possess a 1-D helical chain structure constructed of the 3,4-Hbpt ligands connecting the zinc cations. The [Zn(3,4-bpt)(OAc)] complex demonstrates a 2D sheet structure bridged by tridentate 3,4-bpt-anions. All compounds exhibit substantial thermal stability and show photo-fluorescent properties that result from the ligand π–π* transition. Ultraviolet-to-visible tunable emission for two of the complexes is observed.

Porous inorganic–organic hybrid polymers derived from cyclic siloxane building blocks: Effects of substituting groups on mesoporous structures

Abstract Porous inorganic–organic hybrid polymers (PHPs) with cyclic siloxane frameworks are synthesized via Friedel–Crafts alkylation between siloxane molecules and formaldehyde dimethyl acetal. The synthesized polymers with high specific surface areas (up to 1310 m2 g−1) show a combination of type I(b) and type IV(a) isotherms, as determined by argon adsorption–desorption measurements, suggesting that they contain both micropores and mesopores. Interestingly, two different types of hysteresis loops are observed, depending solely on the organic substituting groups of the siloxane building blocks. PHPs synthesized from cyclic siloxane building blocks substituted with one methyl group and one phenyl group per one silicon atom show type H3 hysteresis loop; while those synthesized from cyclic siloxane building blocks substituted with two phenyl groups show type H2(a) hysteresis loop. This indicates that the resulting PHPs possess different porous networks. 29Si MAS NMR spectra indicate that the Si–phenyl covalent bonds are selectively cleaved during polymerization; while the Si–methyl bonds are not, leading to the formation of different pore structures.

Inorganic–organic hybrid polymer optical planar waveguides for micro-opto-electro-mechanical systems (MOEMS)

The paper reports on the fabrication and characterisation of three types of OrmoClear, OrmoClear®HI01 XP and OrmoClear®FX hybrid polymer optical planar waveguides deposited on glass substrate. The design of the optical planar waveguides was done using a modified dispersion equation; waveguiding properties and refractive indices were measured by dark mode spectroscopy at five wavelengths: 473, 632.8, 964, 1311 and 1552 nm; the measurement showed that the OrmoClear HI01 XP had a higher refractive index value (1.582 at 1552 nm) than the OrmoClear polymer (1.537 at 1552 nm). Optical scattering losses of the waveguides were measured by the fibre scanning method; the measurement showed that the average values of the optical losses of the OrmoClear HI01 XP (0.48 dB/cm) were lower than those of the OrmoClear FX (0.64 dB/cm) and the OrmoClear polymer (0.76 dB/cm) for the measured wavelengths 964, 1311 and 1552 nm. Our measurement showed that the OrmoClear HI01 XP would allow the implementation of the MOEMS structures with higher integration density also in the case of such commonly used substrates as e.g. silica-on-silicon and that our approach would make possible to use low-cost and feasibly elaborated hybrid-polymer-based structures instead of the widely used semiconductor approach.

Organometallic-Organic Hybrid Polymers Assembled from Pentaphosphaferrocene, Bipyridyl Linkers, and CuI Ions.

A multicomponent approach of the Pn ligand complex [Cp*Fe(η5‐P5)] (1: Cp* = η5‐C5Me5) with the ditopic organic linkers 4,4′‐bipyridine (2) or trans‐1,2‐di(pyridine‐4‐yl)ethene (3) in the presence of CuI salts of the anions [BF4]– and [PF6]– or the coordinating anion Br–, leads to the formation of four novel organometallic–organic hybrid polymers: the cationic 1D polymeric compounds [Cu4{Cp*Fe(µ3,η5:1:1‐P5)}2(µ,η1:1‐C10H8N2)4(CH3CN)4]n[BF4]4n (4) and [Cu4{Cp*Fe(µ3,η5:1:1‐P5)}2(µ,η1:1‐C10H8N2)4(CH3CN)4]n[PF6]4n (5) as well as the unique neutral threefold 2D → 2D interpenetrated networks [Cu2Cl2{Cp*Fe(µ3,η5:1:1‐P5)}(µ,η1:1‐C12H10N2)]n (6) and [Cu2Br2{Cp*Fe(µ3,η5:1:1‐P5)}(µ,η1:1‐C10H8N2)]n (7).

Tuning the dimensionality of organometallic–organic hybrid polymers assembled from [Cp2Mo2(CO)4(η2-P2)], bipyridyl linkers and AgI ions

The first of its kind study of the effect of the organic linker length and reaction temperature on aggregation reactions leading to organometallic–organic hybrid polymers is presented.