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1.
Phys Chem Chem Phys ; 26(15): 11988-12002, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38573315

RESUMEN

Ionic liquid crystals (ILCs) combine the ion mobility of ionic liquids with the order and self-assembly of thermotropic mesophases. To understand the role of the anion in ILCs, wedge-shaped arylguanidinium salts with tetradecyloxy side chains were chosen as benchmark systems and their liquid crystalline self-assembly in the bulk phase as well as their electrochemical behavior in solution were studied depending on the anion. Differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS, SAXS) experiments revealed that for spherical anions, the phase width of the hexagonal columnar mesophase increased with the anion size, while for non-spherical anions, the trends were less clear cut. Depending on the anion, the ILCs showed different stability towards electrochemical oxidation and reduction with the most stable being the PF6 based compound. Cyclic voltammetry (CV) and density functional theory (DFT) calculations suggest a possible contribution of the guanidinium cation to the oxidation processes.

2.
J Phys Chem Lett ; 15(12): 3376-3382, 2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-38498994

RESUMEN

Over the years, numerous experimental and theoretical efforts have been dedicated to investigating the mysteries of water and determining its new unexplored physical properties. Despite this, high-pressure studies of water and aqueous mixtures close to the glass transition still represent an unknown area of research. Herein, we address a fundamental issue: the validity of the density scaling concept for fast water dynamics. For this purpose, we performed ambient and high-pressure dielectric measurements of a supercooled equimolar aqueous mixture of an acidic ionic liquid. All isothermal and isobaric relaxation data describing the time scale of charge transport (τσ) and fast dynamics within the water clusters (τν) reveal visual evidence of a liquid-glass transition. Furthermore, both relaxation processes satisfy the ργ/T scaling concept with a single exponent γ = 0.58. Thus, the scaling exponent is a state-point-independent parameter for the dynamics of water clusters confined in ionic liquid investigated in the pressure range up to 300 MPa.

3.
Chem Commun (Camb) ; 60(13): 1747-1750, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38247444

RESUMEN

Dual thermo- and light-responsive water-soluble copolymers that respond to exclusively non-invasive triggers are obtained by functionalising poly(N,N-dimethylacrylamide) with arylazopyrazole side chains. The light-induced E-Z (trans-Z) photo isomerisation of these dyes provides an exceptionally effective photo-switch, which can reversibly shift the LCST-type phase transition temperatures by almost 25 K.

4.
ChemistryOpen ; 13(2): e202300106, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37650312

RESUMEN

We report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long-term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2 O) with the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small-angle X-ray scattering (SAXS), UV-Vis spectroscopy, and MALDI-TOF mass spectrometry. A three-stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz-Slyozov-Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters.

5.
Macromol Rapid Commun ; 44(22): e2300408, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37581256

RESUMEN

Water filtration is an important application to ensure the accessibility of clean drinking water. As requirements and contaminants vary on a local level, adjustable filter devices and their evaluation with contaminants are required. Within this work, modular filter devices are designed featuring an adjustable surface functionalization. For this purpose, 3D-printed structures are created consisting of bio-based poly(lactic acid) (PLA) that are manufactured by extrusion printing. The surface of PLA is activated with amino groups that are used to install xanthates as chain transfer agents. Subsequently, photo-iniferter (PI) polymerization is used to create cationic polymer brushes on the surface of PLA substrates. Multiple surface characterization techniques are employed to prove successful growth of polymer brushes on PLA. After initial optimization studies on flat surfaces, filter devices are printed, functionalized, and used to remove bacteria from contaminated water. Significant reduction of the number of microorganisms is detected after filtration (single filtration or cycling) and contaminating organism can also be removed from freshwater samples by simple incubation with a 3D-printed filter. The herein developed setup for producing functional filter devices and probing their performance in affinity filtration is a useful platform technology, enabling the rapid testing of polymer brushes for such applications.


Asunto(s)
Antiinfecciosos , Agua , Agua/química , Polimerizacion , Polímeros/química , Poliésteres/química , Impresión Tridimensional
6.
Carbohydr Polym ; 318: 121097, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37479430

RESUMEN

Cellulose has attracted interest from researchers both in academic and industrial sectors due to its unique structural and physicochemical properties. The ease of surface modification of cellulose by the integration of nanomaterials, magnetic components, metal organic frameworks and polymers has made them a promising adsorbent for solid phase extraction of emerging contaminants, including pharmaceutical residues. This review summarizes, compares, and contrasts different types of cellulose-based adsorbents along with their applications in adsorption, extraction and pre-concentration of pharmaceutical residues in water for subsequent analysis. In addition, a comparison in efficiency of cellulose-based adsorbents and other types of adsorbents that have been used for the extraction of pharmaceuticals in water is presented. From our observation, cellulose-based materials have principally been investigated for the adsorption of pharmaceuticals in water. However, this review aims to shift the focus of researchers to the application of these adsorbents in the effective pre-concentration of pharmaceutical pollutants from water at trace concentrations, for quantification. At the end of the review, the challenges and future perspectives regarding cellulose-based adsorbents are discussed, thus providing an in-depth overview of the current state of the art in cellulose hybrid adsorbents for extraction of pharmaceuticals from water. This is expected to inspire the development of solid phase exraction materials that are efficient, relatively cheap, and prepared in a sustainable way.


Asunto(s)
Celulosa , Agua , Medios de Contraste , Extracción en Fase Sólida , Preparaciones Farmacéuticas
7.
Biomimetics (Basel) ; 8(3)2023 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-37504217

RESUMEN

Biomimetics (bionics, bioinspired technology) refers to research on living systems and attempts to transfer their properties to engineering applications [...].

8.
ACS Omega ; 8(24): 21594-21604, 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37360480

RESUMEN

New TiO2 hybrid composites were prepared from kaolin clay, predried and carbonized biomass, and titanium tetraisopropoxide and explored for tetracycline (TET) and bisphenol A (BPA) removal from water. Overall, the removal rate is 84% for TET and 51% for BPA. The maximum adsorption capacities (qm) are 30 and 23 mg/g for TET and BPA, respectively. These capacities are far greater than those obtained for unmodified TiO2. Increasing the ionic strength of the solution does not change the adsorption capacity of the adsorbent. pH changes only slightly change BPA adsorption, while a pH > 7 significantly reduces the adsorption of TET on the material. The Brouers-Sotolongo fractal model best describes the kinetic data for both TET and BPA adsorption, predicting that the adsorption process occurs via a complex mechanism involving various forces of attraction. Temkin and Freundlich isotherms, which best fit the equilibrium adsorption data for TET and BPA, respectively, suggest that adsorption sites are heterogeneous in nature. Overall, the composite materials are much more effective for TET removal from aqueous solution than for BPA. This phenomenon is assigned to a difference in the TET/adsorbent interactions vs the BPA/adsorbent interactions: the decisive factor appears to be favorable electrostatic interactions for TET yielding a more effective TET removal.

9.
Macromol Rapid Commun ; 44(16): e2200896, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36703485

RESUMEN

Using the M13 phage display, a series of 7- and 12-mer peptides which interact with new sulfobetaine hydrogels are identified. Two peptides each from the 7- and 12-mer peptide libraries bind to the new sulfobetaine hydrogels with high affinity compared to the wild-type phage lacking a dedicated hydrogel binding peptide. This is the first report of peptides binding to zwitterionic sulfobetaine hydrogels and the study therefore opens up the pathway toward new phage or peptide/hydrogel hybrids with high application potential.


Asunto(s)
Hidrogeles , Péptidos , Hidrogeles/metabolismo , Péptidos/metabolismo , Biblioteca de Péptidos , Bacteriófago M13/genética , Bacteriófago M13/metabolismo
10.
RSC Adv ; 12(54): 35072-35082, 2022 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-36540267

RESUMEN

Eight d-metal-containing N-butylpyridinium ionic liquids (ILs) with the nominal composition (C4Py)2[Ni0.5M0.5Cl4] or (C4Py)2[Zn0.5M0.5Cl4] (M = Cu, Co, Mn, Ni, Zn; C4Py = N-butylpyridinium) were synthesized, characterized, and investigated for their optical properties. Single crystal and powder X-ray analysis shows that the compounds are isostructural to existing examples based on other d-metal ions. Inductively coupled plasma optical emission spectroscopy measurements confirm that the metal/metal ratio is around 50 : 50. UV-Vis spectroscopy shows that the optical absorption can be tuned by selection of the constituent metals. Moreover, the compounds can act as an optical sensor for the detection of gases such as ammonia as demonstrated via a simple prototype setup.

11.
Small ; 18(40): e2203093, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36069261

RESUMEN

The lack of anionic carboxylate ligands on the surface of InP/ZnSe/ZnS quantum dots (QDs), where zinc carboxylate ligands can be converted to carboxylic acid or carboxylate ligands via proton transfer by 1-octanethiol, is demonstrated. The as-synthesized QDs initially have an under-coordinated vacancy surface, which is passivated by solvent ligands such as ethanol and acetone. Upon exposure of 1-octanethiol to the QD surface, 1-octanethiol effectively induces the surface binding of anionic carboxylate ligands (derived from zinc carboxylate ligands) by proton transfer, which consequently exchanges ethanol and acetone ligands that bind on the incomplete QD surface. These systematic chemical analyses, such as thermogravimetric analysis-mass spectrometry and proton nuclear magnetic resonance spectroscopy, directly show the interplay of surface ligands, and it associates with QD light-emitting diodes (QD-LEDs). It is believed that this better understanding can lead to industrially feasible QD-LEDs.


Asunto(s)
Puntos Cuánticos , Acetona , Ácidos Carboxílicos , Etanol , Ligandos , Protones , Puntos Cuánticos/química , Solventes , Compuestos de Sulfhidrilo , Sulfuros , Zinc , Compuestos de Zinc
12.
Chemistry ; 28(64): e202201068, 2022 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-35789121

RESUMEN

Fifteen N-butylpyridinium salts - five monometallic [C4 Py]2 [MBr4 ] and ten bimetallic [C4 Py]2 [M0.5 a M0.5 b Br4 ] (M=Co, Cu, Mn, Ni, Zn) - were synthesized, and their structures and thermal and electrochemical properties were studied. All the compounds are ionic liquids (ILs) with melting points between 64 and 101 °C. Powder and single-crystal X-ray diffraction show that all ILs are isostructural. The electrochemical stability windows of the ILs are between 2 and 3 V. The conductivities at room temperature are between 10-5 and 10-6  S cm-1 . At elevated temperatures, the conductivities reach up to 10-4  S cm-1 at 70 °C. The structures and properties of the current bromide-based ILs were also compared with those of previous examples using chloride ligands, which illustrated differences and similarities between the two groups of ILs.

13.
Nanoscale ; 14(18): 6888-6901, 2022 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-35446331

RESUMEN

Advanced catalysis triggered by photothermal conversion effects has aroused increasing interest due to its huge potential in environmental purification. In this work, we developed a novel approach to the fast degradation of 4-nitrophenol (4-Nip) using porous MoS2 nanoparticles as catalysts, which integrate the intrinsic catalytic property of MoS2 with its photothermal conversion capability. Using assembled polystyrene-b-poly(2-vinylpyridine) block copolymers as soft templates, various MoS2 particles were prepared, which exhibited tailored morphologies (e.g., pomegranate-like, hollow, and open porous structures). The photothermal conversion performance of these featured particles was compared under near-infrared (NIR) light irradiation. Intriguingly, when these porous MoS2 particles were further employed as catalysts for the reduction of 4-Nip, the reaction rate constant was increased by a factor of 1.5 under NIR illumination. We attribute this catalytic enhancement to the open porous architecture and light-to-heat conversion performance of the MoS2 particles. This contribution offers new opportunities for efficient photothermal-assisted catalysis.

14.
Foods ; 11(2)2022 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-35053890

RESUMEN

The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4-8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of ß-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma.

15.
Chempluschem ; 87(1): e202100397, 2021 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-34931472

RESUMEN

Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs.

16.
Materials (Basel) ; 14(14)2021 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-34300916

RESUMEN

Activated carbons (ACs) were prepared from dried spent coffee (SCD), a biological waste product, to produce adsorbents for methylene blue (MB) and methyl orange (MO) from aqueous solution. Pre-pyrolysis activation of SCD was achieved via treatment of the SCD with aqueous sodium hydroxide solutions at 90 °C. Pyrolysis of the pretreated SCD at 500 °C for 1 h produced powders with typical characteristics of AC suitable and effective for dye adsorption. As an alternative to the rather harsh base treatment, calcium carbonate powder, a very common and abundant resource, was also studied as an activator. Mixtures of SCD and CaCO3 (1:1 w/w) yielded effective ACs for MO and MB removal upon pyrolysis needing only small amounts of AC to clear the solutions. A selectivity of the adsorption process toward anionic (MO) or cationic (MB) dyes was not observed.

17.
ACS Appl Mater Interfaces ; 13(26): 30614-30624, 2021 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-34164974

RESUMEN

The use of acidic ionic liquids and solids as electrolytes in fuel cells is an emerging field due to their efficient proton conductivity and good thermal stability. Despite multiple reports describing conducting properties of acidic ILs, little is known on the charge-transport mechanism in the vicinity of liquid-glass transition and the structural factors governing the proton hopping. To address these issues, we studied two acidic imidazolium-based ILs with the same cation, however, different anions-bulk tosylate vs small methanesulfonate. High-pressure dielectric studies of anhydrous and water-saturated materials performed in the close vicinity of Tg have revealed significant differences in the charge-transport mechanism in these two systems being undetectable at ambient conditions. Thereby, we demonstrated the effect of molecular architecture on proton hopping, being crucial in the potential electrochemical applications of acidic ILs.

18.
ChemistryOpen ; 10(2): 272-295, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33751846

RESUMEN

Metal sulfides are among the most promising materials for a wide variety of technologically relevant applications ranging from energy to environment and beyond. Incidentally, ionic liquids (ILs) have been among the top research subjects for the same applications and also for inorganic materials synthesis. As a result, the exploitation of the peculiar properties of ILs for metal sulfide synthesis could provide attractive new avenues for the generation of new, highly specific metal sulfides for numerous applications. This article therefore describes current developments in metal sulfide nanoparticle synthesis as exemplified by a number of highlight examples. Moreover, the article demonstrates how ILs have been used in metal sulfide synthesis and discusses the benefits of using ILs over more traditional approaches. Finally, the article demonstrates some technological challenges and how ILs could be used to further advance the production and specific property engineering of metal sulfide nanomaterials, again based on a number of selected examples.

19.
J Phys Chem B ; 125(13): 3398-3408, 2021 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-33769825

RESUMEN

Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers.

20.
Polymers (Basel) ; 13(2)2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33435604

RESUMEN

New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.

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