Vinylphosphonic Acid Research Articles

Fireproofing wood using borate and vinyl phosphorus compounds and its water resistant treatment using copolymer of dimethyl vinylphosphonate and methyl methacrylate

Vinyl phosphorus compounds such as poly (vinyl phosphonic acid) (PVPA), poly (dimethyl vinyl phosphonate) (PDMVP) impart high flame retardancy to wood comparable to conventional fireproofing wood by combined use of sodium polyborate (SPB) in contrast to their single use. The differential thermal analysis and thermogravimetry (DTA/TG) suggest a synergy effect between SPB and PVPA. The water resistance of the treated wood is improved by copolymerization of dimethyl vinyl phosphonate (DMVP) with methyl methacrylate (MMA) inside the wood after the impregnation of SPB, and the incombustibility of the wood is mostly maintained after leaching tests. The combustion residues of the wood treated with DMVP and MMA after SPB show high compressive strength, and their SEM images suggest that the strength is due to formed charcoal.

Cross-polarization kinetics and fractal nature of thermal equilibration in spin systems: From low-dimensional proton conductors to tripeptides

Cross-polarization with magic-angle spinning (CP MAS) kinetics (1H–13C and 1H–31P) between remote spins were studied in a series of selected materials: from poly-(vinyl phosphonic acid) (pVPA) to calcium hydroxyapatite (CaHA), poly(2-hydroxyethyl methacrylate) (pHEMA), glycine and ultimately to tripeptides (Gly-Pro-Gly, Gly-Phe-Gly and Gly-Gly-Gly). The selection was based on the working concept that the pathways of thermal equilibration in the proton bath should be linked to the structural features of materials. Therefore we attempted to cover the maximal range of dimensionality of conceivable fractal structures as depicted in numerous literature sources. The ‘stretched exponential’ decay was involved in a purely phenomenological way to describe the thermal equilibration during the polarization transfer between remote spins. Its ‘stretching’ index allowed determining the fractal dimensions (Dp) of equilibration pathways. The spin-diffusion model improved by the thermal equilibration in the proton bath was the most appropriate to describe the experimental CP kinetics in the studied series.The fractal dimensions obtained for studied compounds are very reasonable: CaHA and pVPA behave as one-dimensional systems, whereas pHEMA and glycine are close to 2D-systems, and tripeptides can be considered as ‘almost’ 3D-systems. This rational sequence allows us to state that the developed treatment of CP kinetics with included thermal equilibration can reproduce the fractal images of complex compounds. The thermal equilibration is mainly mediated through the strongest interatomic/intramolecular vibrations. In addition to elasticity, a peculiar role of high mobility of protons along H-bonds has to be stressed.

Synergistic Regulation Mechanism of Inorganic Thermal Oxidation Coating and Poly (Vinylphosphonic Acid) (PVPA) Coating for High Load Bearing Superlubricity

A low friction coefficient and high bearing capacity can improve the service life of implants in the human body. In this study, we firstly investigate the mechanical properties of inorganic thermal oxide coatings on titanium alloy (Ti6Al4V). Tribological experiments were performed for different tribo-pairs under uniform conditions. The inorganic thermal oxide coating on Ti6Al4V formed at 300℃ was found to have excellent tribological properties and can effectively improve the bearing capacity of Ti6Al4V. The organic poly (vinylphosphonic acid) (PVPA) on Ti6Al4V has excellent anti-friction properties, which can help achieve superlubricity. An inorganic thermal oxide/organic PVPA composite coating was fabricated on Ti6Al4V to obtain a surface with low friction and high bearing capacity. It is found that the presence of the thermal oxide doubled the bearing capacity of the composite coating compared to that of the PVPA coating alone. This study can serve as a guide for the modification of artificial joints.

Combined Experimental and Theoretical Insights into the Corrosion Inhibition Activity on Carbon Steel Iron of Phosphonic Acids.

The inhibition effect of N,N′-phosphonomethylglycine (PMG) and vinyl phosphonic acid (VPA) on the 3% NaCl acidic solution corrosion of carbon steel iron was studied at different immersion times by potentiodynamic polarization, electrochemical impedance spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and computational methods. It is found from the polarization studies that PMG and VPA behave as mixed-type inhibitors in NaCl. Values of charge transfer resistance (Rct) and double layer capacitance (Cdl) in the absence and presence of inhibitors are determined. The PMG and VPA inhibitors were capable of inhibiting the corrosion process up to ≈91% and ≈85%, respectively. In the presence of PMG, the synergic effect of chlorine ions was observed. Density functional theory (DFT) was engaged to establish the adsorption site of PMG, VPA, and their deprotonated states. For studied compounds, the resulted values of ELUMO, EHOMO, energy gap (∆E), dipole moment (μ), electronic hardness (η), global softness (σ), electrophilic index (ω), and the electronic potential map are in concordance with the experimental data results regarding their corrosion inhibition behavior and adsorption on the metal surface.

Regulation mechanism of biomolecule interaction behaviors on the superlubricity of hydrophilic polymer coatings

Hydrophilic polymer coatings can improve the surface characteristics of artificial implants. However, because they are used in vivo, they inevitably come into contact with biomolecules that affect their interfacial tribological properties. In this paper, the friction behaviors of poly(vinylphosphonic acid) (PVPA)-modified Ti6Al4V and polytetrafluorethylene balls were analyzed using albumin, globulin, aggrecan, and hyaluronic acid as lubricants. The interaction properties and dynamic adsorption characteristics of the biomolecules and PVPA molecules were explored by a quartz crystal microbalance to identify the cause of the friction difference. It was found that protein molecules disturbed the superlubricity of the PVPA-phosphate-buffered saline system because of the formation of a stable adsorption film, which replaced the interfacial characteristics of the PVPA coating. Polysaccharides, with their excellent hydration properties and polymer structure, had an unstable dynamic interaction or zero adsorption with PVPA molecules, and hardly changed the superlubricity of the PVPA and phosphate-buffered-saline system. The influence mechanism of the specific friction of proteins and polysaccharides was analyzed. Interactions were observed among different biomolecules. Polysaccharides can potentially reduce protein adsorption. The result of the synergistic regulation of the friction coefficient for PVPA-modified Ti6Al4V is approximately 0.017. The results of this study will provide a theoretical basis for the use of polymer coatings in vivo.

Biomimetic mineralized microenvironment stiffness regulated BMSCs osteogenic differentiation through cytoskeleton mediated mechanical signaling transduction

Construction of biomimetic microenvironment is vital to understand the relationship between matrix mechanical cues and cell fate, as well as to explore potential tissue engineering scaffolds for clinical application. In this study, through the enzymatic mineralizable collagen hydrogel system, we established the biomimetic bone matrix which was capable of realizing mechanical regulation independent of mineralization by incorporation of phosphorylated molecules (vinylphosphonic acid, VAP). Then, based on the biomimetic mineralized matrix with same composition but significantly different mechanical stiffness, we further investigated the effect of matrix stiffness on osteogenic differentiation of bone marrow stromal cells (BMSCs). The results clearly demonstrated that biomimetic mineralized microenvironment with higher mechanical strength promoted osteogenic differentiation of BMSCs. Further mechanism analysis demonstrated that the mineralized hydrogel with higher stiffness promoted cytoskeletal assembly, which enhanced the expression and nuclear colocalization of YAP and RUNX2, thereby promoted the osteogenic differentiation of stem cells. This study supplies a promising material platform not only for bone tissue engineering but also for exploring the mechanism of biomimetic bone matrix mechanics on osteogenesis.

Molecular Motions of Imidazole in Poly(vinylphosphonic acid)-Imidazole Composites Investigated by Molecular Dynamics Simulations

Abstract Poly(vinylphosphonic acid)-imidazole (PVPA-xIm) exhibits high proton conductivity above 100 °C. The high proton conductivity of PVPA-2Im depends on the molecular motions of Im. Molecular dynamics simulations conducted herein showed that the intercalation of Im and imidazolium into PVPA reduces the translational motion of Im in PVPA-2Im. The activation energy of the internal motion of Im is lower than that of the translational motion, indicating that proton conduction in PVPA-2Im occurs via a Grotthuss-type mechanism.

Synthesis and characterization of poly(TRIM/VPA) functionalized graphene oxide nanoribbons aerogel for highly efficient capture of thorium(IV) from aqueous solutions

An ultralight three-dimensional porous network phosphonic acid functionalized polymer/graphene oxide nanoribbons aerogel (PAFP/GONRs-A) was prepared using trimethylolpropane trimethacrylate (TRIM) and vinylphosphonic acid (VPA) as monomers via solvothermal polymerization method for thorium capture from aqueous solutions. The synthesized aerogel presented a low density (10.6 mg cm−3), large specific surface area (433.2 m2 g−1) and high phosphorus content (18.2%). The adsorption process of Th(IV) on PAFP/GONRs-A was pH-dependent, spontaneous and endothermic, and well described by the pseudo-second-order kinetic and Langmuir isotherm model. Under optimal experimental conditions (10 mg of adsorbent dosage, 50 mL of solution volume, 240 min of contact time, 298 K of temperature), PAFP/GONRs-A presented an excellent high adsorption capacity of thorium, with maximum capacity of 457.9 mg g−1 at a pH of 3.0, and maximum thorium-selectivity of 87.1% at a pH of 2.0. The values of ΔG for Th(IV) adsorption on PAFP/GONRs-A were calculated to be −21.78, –23.32, −24.87 and −26.41 kJ mol−1 at 283, 298, 313 and 328 K, respectively. Density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) revealed that Th(IV) ions were fixed in aerogel by coordinating with the P = O groups of PAFP/GONRs-A, and both 1:2 ratio of Th(IV) with the P = O ligands on the same graft chain and 1:4 ratio of Th(IV) with P = O ligands on two distinct graft chains could jointly contribute to the adsorption of Th(IV) on PAFP/GONRs-A. This work offers a facile approach for synthesizing the phosphonic acid functionalized graphene oxide nanoribbons aerogel and demonstrates that PAFP/GONRs-A has high potential as a candidate adsorbent for the capture of thorium from aqueous solution.

Determination of 2-chloroethylphosphonic acid and its intermediate vinylphosphonic acid from artificially ripened sapota fruit by modified dispersive solid-phase extraction cleanup and gas chromatography/mass spectrometry analysis.

Fruit is generally ripened after harvesting using artificial ripeners such as ethylene, calcium carbide, and ethephon (2-chloroethylphosphonic acid), which can release some residues into the fruits. These residues must be within the maximum levels described in various international standards. The presence of the residues of artificial ripeners must be verified using sensitive and selective detection methods. The residues of ethephon and vinylphosphonic acid (VPA) were extracted from the pulp of sapota fruit using acetone, and the extract was treated with MgSO4 to remove residual water. The extract was subjected to dispersive solid-phase extraction cleanup using DSC-6S sorbent and graphitized carbon black mix, and the cleaned sample was evaporated to dryness and reconstituted in ether containing diazomethane. The analytes were quantitatively identified using gas chromatography/mass spectrometry. The developed method was observed to be linear in the concentration range of 1-5000 ng/g, and the limits of detection and quantification of the method were 1 and 2 ng/g, respectively, for both ethephon and VPA residues. The inter-day and intra-day precision was below 15%. The developed method was used for the quantification of ethephon residues from sapota fruit ripened with 100, 200, 500, 1000, 5000, and 10 000 mg/L solutions of ethephon, and ethephon residues were detected in the pulp samples up to a concentration of 5 ng/g. VPA residues were not detected in the fruit pulp; however, the washing solution of fruit ripened with a 10 000 mg/L ethephon solution showed VPA residues. The validated method exhibited high sensitivity for the analytes with a limit of quantification of 2 ng/g, which is lower than the described maximum residue level of 0-5 μg/g. The ethephon residues were below the maximum residue limits in the pulp of sapota fruit ripened with ethephon solutions up to 10 000 mg/L concentration.

Phosphonate metal–organic frameworks used as dye removal materials from wastewaters

A very intense study class of complex porous materials, metal–organic frameworks (MOFs), composed of diverse central metallic ions attached to organic linkers, was used in this study as adsorbant materials from wastewaters. Phosphonate MOFs were prepared by the reaction of divalent inorganic salts (CoSO4·7H2O, NiSO4·6H2O, CuSO4·5H2O,) with vinyl phosphonic acid in hydrothermal conditions, obtaining cobalt, nickel, and copper vinylphosphonate (CoVP, NiVP, and CuVP). During synthesis the experimental conditions were varied in terms of time, temperature, and pH. The synthesized materials were characterized by Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and X‐ray crystallography. The efficiency of MOFs as adsorbents was investigated for diverse initial dye concentrations at different pH values and at three temperatures (25, 40, and 55°C). The synthesized materials presented good efficiency in the elimination of anionic as well as cationic type of dyes from aqueous solutions. The highest adsorption capacities were obtained working at optimum solution pH 4.2 for Acid Orange 7 and 10 for Basic Fuchsine, using 1 g/L of MOFs at room temperature (25°C). The adsorption capacities increase in the following order: CuVP < NiVP < CoVP.

Under-oil superhydrophilic TiO2/poly(sodium vinylphosphonate) nanocomposite for the separation of water from oil

Under-water superoleophobic filters lose their water separation capability if they are contaminated with oil. In contrast, an oil contaminant in a filter that is both superoleophobic underwater and superhydrophilic underoil can be readily displaced with water. Even after contamination by oil, such a filter can self-clean in water and re-create and maintain an integral water film in the pores to enable sustained water separation. Unfortunately, there have been only a few reported examples of under-oil superhydrophilic materials. We report herein a novel under-oil superhydrophilic material consisting of TiO2 nanoparticles that are coated by an excess of a sodium salt of poly(vinylphosphonic acid) (PVPA.nNa). This nanocomposite can be applied as a coating onto various substrates such as glass plate, glass wool, cotton ball, and stainless-steel metal mesh for permanent self-cleaning and hexadecane collection. More interestingly, a coated cotton ball could be affixed to the bottom end of a standing tube and allows the selective permeation of water from a stirred water/hexadecane mixture. Unfortunately, a coated metal mesh with larger pores and thus much higher water flux could not achieve the separation most likely because the weakness of the water film in the mesh pores induces a negative value of Laplace pressure. We achieve this separation for the coated metal mesh by attaching a thin electrospun superhydrophobic mat onto its lower side to thus yield a Janus filter. Our assumption is that the unidirectional upward water-pulling force of the Janus filter in this case helps to stabilize the water film in the metal mesh. Due to the facile synthesis of TiO2-PVPA·nNa and the demonstrated applications of the TiO2-PVPA·nNa coating, this study should inspire further research in high-flux filters for water separation from oil.

Influence of lignocellulosic substrate and phosphorus flame retardant type on grafting yield and flame retardancy

Various phosphorus flame retardants (FR) have been grafted on lignin-rich miscanthus fibers and lignin-poor flax fibers according to two methods, phosphonic acids condensation in mild conditions and radiation grafting. Phosphorus content and its location on fibers were evaluated. Even if phosphorus FR diffused into the fibers bulk in all cases, chemical modification based on phosphonic acids condensation with hydroxyls of miscanthus fibers appears more suitable for high lignin content fibers. Phosphorus content in miscanthus fibers reached 1.4 wt% using hexane-1,6-diylbisphosphonic acid whereas it reached a lower content (0.3 wt%) for flax fibers. Radiation grafting is suitable for both fibers with limited effect depending on fiber nature. Flame retardancy at microscale was examined using PCFC and TGA. Thermal properties and flame retardancy have been shown to be correlated to the phosphorus content but also to fibers composition and to the thermal stability of the flame retardant. Vinyl phosphonic acid was found to be more efficient as char promoter for flax compared to miscanthus.

Phase-Controllable Cobalt Phosphides Induced through Hydrogel for Higher Lithium Storages.

Transition metal phosphides (TMPs) have gained increased attention in energy storage due to their potential applications for optimizing electrochemical performances. However, their preparation routes usually require highly toxic and flammable phosphorus sources with strict reaction conditions. The existence of multiple energetically favorable stoichiometries also makes it a challenge to achieve phase control of metal phosphides. In this work, we have successfully realized the phase-controllable framework of cobalt phosphide from Co2P to CoP by employing a semi-interpenetrating network (semi-IPN) hydrogel as a precursor. Interestingly, the semi-IPN hydrogel could serve as a self-assembly/sacrificing template to accomplish 3D space confinement, where poly(vinylphosphonic acid) (PVPA) was identified as a prominent phosphorus source due to its strong metal complexation ability and high thermal stability. Furthermore, this route is successfully extended to the synthesis of other TMPs, including Fe2P, Ni2P, and Cu3P. The specific structure of cobalt phosphides gives rise to superior lithium storage performance, showing superior cycling stability (495.2 mAh g-1 after 1000 cycles at 2.0 A g-1). This approach envisions a new outlook on exploitation of essential functional hydrogels for the creation of inorganic materials toward sustainable energy development.

Surface passivation of zero-mode waveguide nanostructures: benchmarking protocols and fluorescent labels

Zero mode waveguide (ZMW) nanoapertures efficiently confine the light down to the nanometer scale and overcome the diffraction limit in single molecule fluorescence analysis. However, unwanted adhesion of the fluorescent molecules on the ZMW surface can severely hamper the experiments. Therefore a proper surface passivation is required for ZMWs, but information is currently lacking on both the nature of the adhesion phenomenon and the optimization of the different passivation protocols. Here we monitor the influence of the fluorescent dye (Alexa Fluor 546 and 647, Atto 550 and 647N) on the non-specific adhesion of double stranded DNA molecule. We show that the nonspecific adhesion of DNA double strands onto the ZMW surface is directly mediated by the organic fluorescent dye being used, as Atto 550 and Atto 647N show a pronounced tendency to adhere to the ZMW while the Alexa Fluor 546 and 647 are remarkably free of this effect. Despite the small size of the fluorescent label, the surface charge and hydrophobicity of the dye appear to play a key role in promoting the DNA affinity for the ZMW surface. Next, different surface passivation methods (bovine serum albumin BSA, polyethylene glycol PEG, polyvinylphosphonic acid PVPA) are quantitatively benchmarked by fluorescence correlation spectroscopy to determine the most efficient approaches to prevent the adsorption of Atto 647N labeled DNA. Protocols using PVPA and PEG-silane of 1000 Da molar mass are found to drastically avoid the non-specific adsorption into ZMWs. Optimizing both the choice of the fluorescent dye and the surface passivation protocol are highly significant to expand the use of ZMWs for single molecule fluorescence applications.

Local Structures and Dynamics of Imidazole Molecules in Poly(vinylphosphonic acid)–Imidazole Composite Investigated by Molecular Dynamics

The composite materials of acidic polymers and imidazole (Im) exhibit good high-proton conduction, making them potentially useful in proton-exchange membrane fuel cells. The proton conduction mechanism must be clearly elucidated for the design of future high proton-conduction materials. This study examines the local hydrogen-bonding structures and dynamics of Im for proton-conducting poly(vinylphosphonic acid)-Im (PVPA-xIm) composites by using molecular dynamics simulations. Radial distribution functions (RDFs) characterize the hydrogen bonds between Im or imidazolium cation (ImH+) and phosphonic acid (PA) group and among Im molecules. RDFs and diffusion coefficients suggest that the intercalation of Im to PVPA reduces Im mobility because of the interaction between Im and PA groups. However, similar to pure Im, the amount of Im with fast rotational motions increases as the amount of Im increases. Our study leads us to conclude that long-range proton transport occurs through the hydrogen-bonding network of...

A novel prime-&-rinse mode using MDP and MMPs inhibitors improves the dentin bond durability of self-etch adhesive

ObjectivesThe study investigated the effects of novel prime-&-rinse mode using MDP (10-methacryloyloxydecyl dihydrogenphosphate) and matrix metalloproteinase (MMPs) inhibitors on dentin microtensile bond strengths (MTBS) of self-etch adhesive, resin-dentin interface degradations, and activity of recombinant human (rh) MMP-8, -9. Materials and methodsEight experimental primers were prepared using 5% and 15% of MDP ethanol-aqueous (1:1) solution in combination with/without MMPs inhibitors (1%benzalkonium chloride (BAC), 1000 μm/mL polyvinylphosphonic acid (PVPA) and 15%proanthocyanidin (PA)). Ninety human mid-coronal dentin surfaces were applied with the experimental primers, water-sprayed and gently air-dried (prime-&-rinse mode), or not (control, self-etch mode). The specimens were bonded with self-etch adhesive (Clearfil S3 Bond) and composite resin (Clearfil Majesty). The resin-bonded specimens were prepared into multiple micro-beams for MTBS tests after 24 h and 1 yr of water storage. The resin-dentin interfaces were analyzed with SEM/TEM. The inhibitory effects of eight primers on rhMMP-8, 9 were determined. The data were analyzed using two-way ANOVA and LSD multiple comparisons tests. ResultsCompared with control, all the primers used in prime-&-rinse mode could significantly improve long-term dentin MTBS (P < 0.05), while 5%MDP-BAC, 15%MDP and 15%MDP+MMPs inhibitors could significantly increase the short-term dentin MTBS (P < 0.05). The SEM/TEM findings revealed that the resin-dentin interfaces were stable over time when the prime-&-rinse mode used. Eight primers possessed the high inhibitory ratio of rh MMP-8, 9. ConclusionsThe novel prime-&-rinse mode using 5%MDP-BAC, 15%MDP and 15%MDP+MMPs inhibitors could significantly increase the short- and long-term dentin MTBS of self-etch adhesive. This might be a supplement to contemporary dentin bonding strategies.

Organo-Inorganic Hybrid Intumescent Fire Retardant Coatings for Thermoplastics Based on Poly(Vinylphosphonic Acid).

Thin coatings of crosslinked poly(vinylphosphonic acid), PVPA, display good adhesion and excellent intumescent, fire-retardant barrier properties when applied to the surfaces of a typical thermoplastic, such as poly(methyl methacrylate), but perform relatively poorly in water-soak tests. To strengthen and further improve the barrier properties of the intumescent char and to make the coating more hydrophobic, PVPA has been complexed with various inorganic and organic species. The chars formed from coatings of some of these hybrid materials are less friable than chars from coatings synthesized from crosslinked PVPA alone, and show higher levels of water tolerance with no significant reduction in dry adhesion to the substrate.

Polymers of vinylphosphonic acid, acrylonitrile, and methyl acrylate and their nanofibers

AbstractIn this study, a small amount of vinylphosphonic acid was used to produce fire‐retardant copolymers and terpolymers from acrylonitrile and methyl acrylate. The structures of copolymer and terpolymers were elucidated by 1H‐NMR and phosphorous analysis. Thermal decomposition of vinylphosphonic acid‐containing copolymers and terpolymers started at lower temperatures than of poly(acrylonitrile‐co‐methyl acrylate). Methyl acrylate contributes to the thermal resistance of the terpolymers. Poly(acrylonitrile‐co‐methyl acrylate‐co‐vinylphosphonic acid) with a phosphorous content about 0.25% burned at a slower rate and emitted less smoke compared to poly(acrylonitrile‐co‐methyl acrylate). The burning tests showed that both copolymer and terpolymers containing vinylphosphonic acid behaved as a fire‐retardant polymer. The phosphonate and phosphonic acid groups in the copolymer and terpolymers accelerate the cyclization of nitrile groups and inhibit the fire in the gas phase. Nanofibers were successfully produced by the electrospinning method from the copolymers and terpolymers containing vinylphosphonic acid moiety.

Design of Crosslinked Hydrogels Comprising Poly(Vinylphosphonic Acid) and Bis[2-(Methacryloyloxy)Ethyl] Phosphate as an Efficient Adsorbent for Wastewater Dye Removal.

The development of adsorbents with high adsorption capacity and fast separation is of utmost importance for the environmental management of dye-bearing wastewaters. Within this scope, crosslinked hydrogels including poly(vinylphosphonic acid) (PVPA) and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) were designed with varying mole ratios of BMEP (5–40%). The Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) results revealed that the fabrication of crosslinked PVPA-BMEP hydrogels enhanced: (i) functionalities of PA groups in the structure of hydrogels, (ii) thermal stabilities up to 250 °C, and (iii) interaction between methylene blue (MB) molecules and hydrogels. The pseudo second-order kinetic model best described the experimental adsorption data. The behaviors of the isotherms were more appropriate for Langmuir than Freundlich isotherm for the experimental data. PVPA-BMEP (40%) hydrogel indicated a fast and an outstanding MB adsorption capacity of 2841 mg g−1, which has not been reported yet for polymer hydrogels, to the best of our knowledge. The thermodynamic studies concluded that MB adsorption process was spontaneous and exothermic in nature. The overall results suggest that the designed and fabricated PVPA-BMEP hydrogels have great potential for the efficient removal of coloring materials from wastewaters.

Synthesis of a Bolaamphiphilic Alkenyl Phosphonic Acid by Ru-catalyzed Olefin Cross Metathesis Reaction.

We report the synthesis of bolaamphiphilic alkenyl phosphonic acid (BPC12) through the olefin crossmetathesis reaction of vinylphosphonic acid with 1,11-dodecadiene in the presence of a Ru-carbene catalyst. BPC12 possesses two trans-P-C=C moieties and is thus readily soluble in water up to 3.4 g L-1, as confirmed by 1H nuclear magnetic resonance (NMR) measurements. Surface tension measurements revealed that BPC12 reduced the surface tension of water from 72.0 to 47.0 mN m‒1. The occupied area per molecule at the air/water interface (A) of BPC12 (216 Å2) was ten times larger than that of dodecenyl phosphonic acid PC12 (23 Å2). Moreover, dynamic light scattering measurement of an aqueous BPC12 solution (5 mM) revealed the formation of large aggregates with an average diameter of 81.8±27.0 nm.