Hot Organic Solvents Research Articles

Recycling of expired cow milk for constructing multifunctional biomass nonfluorinated chromatic paint with superhydrophobicity

Through denaturation and amination of the mixture, consisted of expired cow milk, kaolin and gardenia yellow, in the hot organic solvent that contained alkaline aminosilane coupling agent, then adsorption of diverse acid dyes in the acid condition, thus obtaining active matrixes with different colors. By virtue of the non-catalyzed in-situ reaction among the acrylate groups of pentaerythritol ester compounds and the amino groups of obtained matrixes as well as long-chain alkyl amines, the biomass fluoride-free superhydrophobic doped paints was prepared, however the poor stability was reflected in its anti-wetting coating surface. Furthermore, in order to improve durable superhydrophobicity and multifunctionality of the expired cow milk-based water-repellent paint, the thermally denatured protein, originated from expired cow milk heating, was blended with nanoscale inorganic pigments to accept the before-mentioned procedures of amination and in-situ growth, consequently constructing the multifunctional biomass nonfluorinated chromatic paint with robust superhydrophobic function, moreover its coated fabrics had 155.7° of average contact angle and 1.5° of average sliding angle. Additionally, by only using synergy of complex denaturation and chemical coupling, the expired cow milk could be transformed into UV-photoluminescent nonfluorinated superhydrophobic color paint, the contact angle of such paint-coated fabric was 153.3° and its sliding angle was 2°. Based on the additional function of as-prepared biomass paints, the applications of non-wetted switchable fluorescence imaging as well as photothermal deicing were realized. We believe that the expired cow milk-based multifunctional paints can expand into the fields of outdoor protective textiles, decorative building materials, fluorescent falsification-preventing and ice protection.

Methods of recycling of lithium power sources

Today, there are technologies for recycling lithium power sources, but they are not yet satisfactory and cost-effective. The purpose of the study - based on the analysis of scientific and technical publications to formulate a general description of modern technologies for recycling lithium power sources. The second purpose is to present the results of the authors' research on the improvement of lithium battery recycling technologies. Based on the analysis of scientific and technical publications, a general description of modern technologies for processing lithium power sources is given. Processing is carried out according to the following scheme. First, they organize the discharge of power sources and their pre-treatment to separate the active substances. Pre-treatment is carried out by mechanical grinding, or ultrasound, or calcination or solvents. Mechanical crushing is performed in blade crushers. Machining is the most common method of separating lithium batteries. However, it has disadvantages: loud noise, emissions of dust and harmful gases. Calcination takes place at temperatures up to 500 ° C to remove carbon and organic material. Disadvantages of the method: calcination requires expensive equipment, is energy-intensive and can emit toxic gases. Solvent pre-treatment uses solutions and solvents to separate the active materials from Al, Cu foil in the battery. This method removes the addition of binder material, which increased the contact of the foil with the active materials. Disadvantages: this method requires the use of hot organic solvents of about 100˚C, which increases the cost and creates hazardous waste into the environment. More promising is the method of processing batteries in ultrasonic cavitation. The pre-treated material is subjected to magnetic or gravitational separation, removing substances containing metals. Then Li, Co, Ni, Mn are removed by pyrometallurgy, or hydrometallurgy, or electrochemical extraction. The obtained metals are suitable for secondary use in lithium power sources. The analysis of the considered technologies of processing of lithium power sources indicates that an important way to increase the efficiency of recycling is to improve the quality of pre-treatment of products that have exhausted the resource, which allows to effectively remove active materials with the lowest energy costs and environmental risks. The authors have developed a schematic diagram of the technology of pre-treatment of lithium batteries based on acoustic or hydrodynamic cavitation, as well as improved the method of magnetic separation of metals.

Long-Chain Polyorthoesters as Degradable Polyethylene Mimics.

The persistence of commodity polymers makes the research for degradable alternatives with similar properties necessary. Degradable polyethylene mimics containing orthoester groups were synthesized by olefin metathesis polymerization for the first time. Ring-opening metathesis copolymerization (ROMP) of 1,5-cyclooctadiene with four different cyclic orthoester monomers gave linear copolymers with molecular weights up to 38000 g mol–1. Hydrogenation of such copolymers produced semicrystalline polyethylene-like materials, which were only soluble in hot organic solvents. The crystallinity and melting points of the materials were controlled by the orthoester content of the copolymers. The polymers crystallized similar to polyethylene, but the relatively bulky orthoester groups were expelled from the crystal lattice. The lamellar thickness of the crystals was dependent on the amount of the orthoester groups. In addition, the orthoester substituents influenced the hydrolysis rate of the polymers in solution. Additionally, we were able to prove that non-hydrogenated copolymers with a high orthoester content were biodegraded by microorganisms from activated sludge from a local sewage plant. In general, all copolymers hydrolyzed under ambient conditions over a period of several months. This study represents the first report of hydrolysis-labile and potentially biodegradable PE mimics based on orthoester linkages. These materials may find use in applications that require the relatively rapid release of cargo, e.g., in biomedicine or nanomaterials.

COMPLEXES OF IZOTHIADIAZOLE-CONTAINING BROMONITROSUBSTITUTED THREE UNITS PRODUCT WITH D-METALS (NI, CO, ZN)

This work is continuation of synthesis researches of substituted macroheterocyclic compounds with 1,2,4-thiadiazole fragments. Data of synthesis of complexes with divalent d-metals (Ni, Co, Zn) on the basis of received earlier brominenitrosubstituted isothiadiazole three-unit product are presented. Complexes of BAB-type product consisting 1,2,4-thiadiazole and bromine-nitro-isoindole fragments were received by interaction 3,5-bis-[5(6)-bromine-6(5)-nitro-3-iminoizoindolin-1-ilidenamiino]-1,2,4-thiadiazol with acetates of d-metals in 2-ethoxyethanol at 100 ºC for 2 h. After the reaction the mixture was poured into water and precipitate was filtered and washed with 5 % ammonia, water and hot organic solvents (acetone, methanol, dimethylformamide, pyridine). Yield of target products was 18 – 28 %. The resulting complexes are dark brown powders with high solubility in alcohols, DMF, insoluble in water, dichloromethane and hexane. The structures of products were established by data of mass spectrometry, elemental analysis, UV-vis and IR spectroscopy. Data of MALDI-TOF mass spectrometry showed that complexes with metal of three-unit product with 1,2,4-thiadiazole fragment were isolated as monohydrate by analogy with literary for 1,3,4-thiadiazole. Data of atomic absorption analysis with good convergence of the experimental and calculated values confirmed monohydrate structure these products. These complexes of three-unit products will be used for synthesis of new various substituted macroheterocycles with 1,2,4-thiadiazole fragments.
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Synergistic Effect of the Methanolic Extract of Lemongrass and Some Antibiotics to Treat Urinary Tract Bacteria

Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana cama-ra), and wild olive leaves (Olea europaea) were collected, identified, extracted with either hot water or organic solvents (methanol, diethyl ether, ethyl acetate and n-butanol) to investigate their antibacterial activities against E. coli. The methanol ex-tracts of lemongrass, lantana and olive showed the highest activities against Esherichia coil while aqueous extract exhibited the lowest activities. Thus, the antibacterial activities of the methanolic extract of the three tested plants were determined using agar well diffusion method against some bacterial pathogens, isolated from urine samples. The highest antibacterial activity was recorded for themethanolic extract of lemongrass against all tested bacteria, E. coli, K. pneumoniae, P. aeuroginosa, P. mirabilis, E. faecalis and S. aureus. The tested bacteria differed with regard to their susceptibility to plant extracts. Lemongrass was the most active extract followed by lantana and wild olive extracts. Minimal inhibitory concentrations (MICs) of the methanolic extract of Lemongrass and some used antibiotics, Erythromycin, Tetracycline, Amoxicillin, Ciprofloxacin and Chloramphenicol were determined usingfluorescein diacetate method. Synergistic effect of the methanolic extract of lemongrass with the previous antibiotics against the tested clinical bacterial isolates was determined and the Fractional inhibitory concentrations (FIC) of different combination of the extract and the antibiotics were determined. FIC index (FICI) was calculated and it was ranged from 0.08 - 0.98. The interaction between the tested plant extract and the tested antibiotics was either synergistic or additive effects and no antagonistic effect was recorded. In conclusion, methanolic extract of lemongrass singly or in combination with some antibiotics can be used to treat pathogenic bacteria that cause urinary tract infections.

Synthesis and Characterization of SPIONs for Biomedical applications

This work reports the synthesis and characterization of superparamagnetic iron oxide nanoparticles (SPIONs), with great potential for biomedical applications. SPIONs were prepared through a decomposition of Fe(acac)3 in the presence of 1,2 hexadecanodiol (reducing agent), oleic acid and oleylamine (ligands) in a hot organic solvent. The mercaptosuccinic acid (MSA) and 2,3- dimercaptosuccinic acid (DMSA) were exchanged onto the nanocrystal surface making the particles stable in water. The thiolated nanoparticles (SH-NPs) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The as-prepared sample presented an amorphous partially oxidized iron structure. The results showed that the SH-NPs have a mean diameter of 6 nm and display superparamagnetic behavior at room temperature. Preliminary tests of incorporation of these systems were evaluated in Hela cells and stem cells. The results showed that the thiolated nanoparticles have no toxic effects for both cell types with good incorporation after 6 hours of transfection. Magnetic resonance image (MRI) were also carried and showed that the MNPs increase the contrast in systems investigated. Acknowledgements: FAPESP (2011/10125-0), CNPq, CAPES, UNICAMP

Efficient thermolysis route to monodisperse Cu₂ZnSnS₄ nanocrystals with controlled shape and structure.

Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals with tunable shape, crystalline phase, and composition are synthesized by efficient thermolysis of a single source precursor of mixed metal-oleate complexes in hot organic solvents with dissolved sulfur sources. Suitable tuning of the synthetic conditions and the Cu/(Zn + Sn) ratio of the precursor has enabled precise control of the crystalline phase in the form of kesterite, or a newly observed wurtzite structure. Nanocrystals with morphology in the form of spherical, rice-like, or rod-like shapes are obtained over a wide range of compositions (0.5 ≤ Cu/(Zn + Sn) ≤ 1.2). Both the final products and intermediates for each shape exhibit consistent composition and structure, indicating homogenous nucleation and growth of single-phase nanocrystals. Thin films prepared from colloidal nanocrystal suspensions display interesting shape-dependent photoresponse behavior under white light illumination from a solar simulator.

Near-IR Sensitization of ZnO Rod Electrode By Non-Toxic Ag8SnS6 Nanoparticles

Introduction Near-Infrared (NIR) light-responsive semiconductor nanoparticles have attracted much attention as an efficient light absorbing material in quantum dot solar cells due to their suitable energy gap for solar light spectrum. Furthermore, semiconductor nanoparticles with narrow energy gap have a potential to exceed the theoretical conversion efficiency of conventional solar cells by utilizing their unique physicochemical properties such as the increase in the probability of multiple exciton generation and the hot electron injection. So far binary chalcogenide semiconductor nanoparticles (e.g. CdTe, PbS and PbSe) have intensely investigated for their use in quantum dot solar cells, but the application of these semiconductor nanoparticles appears to be more and more limited due to the high toxicity of Cd or Pb in view of the recent environment regulations. A multinaly chalcogenide of Ag8SnS6(ATS) with energy gap of NIR region contains only non-toxic elements seems to be one of the most potential alternatives for conventional toxic nanoparticles. However there was no report about the preparation of colloidal ATS nanoparticles.Here we report the preparation of ATS nanoparticles in hot organic solvent and investigated their photosensitization abilities of ZnO rod electrode. Experimental ATS nanoparticles were prepared by thermal decomposition of organic metal complexes in oleylamine at various reaction temperatures under N2 atmosphere. ZnO nanorods were deposited on fluorine-doped SnO2 (FTO) in an aqueous solution containing hexamethylenetetramine and zinc nitrate.[1] ATS nanoparticles are immobilized on ZnO rod/FTO electrode by dip-coating technique. The ZnO rod electrode was dipped for 10 second into ATS nanoparticles solution and pulled at a rate of 1 cm min-1. Un-adsorbed particles were removed by immersing into ethanol. These dip-coating and washing cycles were repeated for 30 sets to densely immobilized ATS on ZnO rod electrodes (ATS/ZnO rod). Thus-obtained ATS/ZnO electrode was irradiated in acetonitrile solution containing triethanolamine as a hole scavenger, using 300 W Xe lamp (λ>350 nm). The potential was determined against an Ag/AgCl (sat. KCl) reference electrode and a Pt wire was used as a counter electrode. Results and discussions XRD patterns of obtained particles exhibited broad peaks, which were assignable to diffraction of orthorhombic ATS. The absorption spectrum (Fig. 1a) of ATS nanoparticles prepared at 200°C had an absorption onset around 920 nm, being corresponding to the reported energy gap of bulk ATS (1.35 eV). TEM observation revealed that spherical particles were formed at 200°C (Fig. 1b). The particle size could be controlled from 7 to 13 nm only by changing the reaction temperature from 150°C to 350°To investigate the ability of ATS nanoparticles as a photosensitizer, we immobilized them onto a ZnO rod electrode by dip-coating technique. The immersion of ZnO rod electrode in ATS solution changed their color from white to black. Diffuse reflectance spectra of the thus-obtained films agreed well with absorption spectra of corresponding ATS nanoparticles in solution. Figure 2 shows SEM images of thus-obtained ZnO rod electrodes before and after deposition of ATS nanoparticles. It was found that ATS nanoparticles fully covered the surface of ZnO rod.The irradiation to ATS/ZnO rod electrodes immersed in the acetonitrile solution containing triethanolamine produced an anodic photocurrent, the intensity being much larger than that of the ZnO rod electrode. These results indicated that ATS/ZnO exhibited the similar behavior of n-type semiconductor photoelectrodes. Action spectra of photocurrent exhibited the onset wavelength at ca. 1000 nm, being in good agreement with the absorption onset wavelength observed in diffuse reflectance spectra of the corresponding electrodes. These results indicated that ATS nanoparticles effectively worked as a photosensitizer driven by irradiation of visible and NIR light (λ<1000 nm). Reference [1] Y. J. Lee et al., J. Cryst. Growth., 2007, 304, 80.

Inhibition of DNA polymerase λ and associated inflammatory activities of extracts from steamed germinated soybeans

During the screening of selective DNA polymerase (pol) inhibitors from more than 50 plant food materials, we found that the extract from steamed germinated soybeans (Glycine max L.) inhibited human pol λ activity. Among the three processed soybean samples tested (boiled soybeans, steamed soybeans, and steamed germinated soybeans), both the hot water extract and organic solvent extract from the steamed germinated soybeans had the strongest pol λ inhibition. We previously isolated two glucosyl compounds, a cerebroside (glucosyl ceramide, AS-1-4, compound ) and a steroidal glycoside (eleutheroside A, compound ), from dried soybean, and these compounds were prevalent in the extracts of the steamed germinated soybeans as pol inhibitors. The hot water and organic solvent extracts of the steamed germinated soybeans and compounds and selectively inhibited the activity of eukaryotic pol λ in vitro but did not influence the activities of other eukaryotic pols, including those from the A-family (pol γ), B-family (pols α, δ, and ε), and Y-family (pols η, ι, and κ), and also showed no effect on the activity of pol β, which is of the same family (X) as pol λ. The tendency for in vitro pol λ inhibition by these extracts and compounds showed a positive correlation with the in vivo suppression of TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation in mouse ear. These results suggest that steamed germinated soybeans, especially the glucosyl compound components, may be useful for their anti-inflammatory properties.

Phase-Controlled Synthesis of Cu2ZnSnS4 Nanocrystals: The Role of Reactivity between Zn and S

Cu2ZnSnS4 (CZTS) nanocrystals with different morphologies and phases have been synthesized in hot organic solvents such as dodecanethiol and oleylamine. The crystallographic phases could be controlled by the sulfur precursor and the ligand species of the metal salts used for the synthesis. When a highly reactive sulfur precursor and metal acetates were used, wurtzite CZTS nanocrystals were obtained. On the other hand, using a low-reactivity sulfur precursor or metal chlorides produced CZTS nanocrystals in a kesterite phase. The experimental results from systematic investigations indicated that the reaction rate between Zn and S precursors played a determining role for the growth of CZTS nanocrystals with different crystalline phases. A relatively faster reaction between Zn and S precursors in comparison to the Sn-S reaction favored the formation of a metastable wurtzite phase, which could be accelerated by increasing the reactivity of the S precursor. This work provided a safe and economical way to synthesize high-quality phase-controlled Cu2ZnSnS4 nanocrystals, especially wurtzite nanorods, for potential photovoltaic applications. Moreover, preliminary results show that the proposed mechanism also applies to the phase-controlled synthesis of other quaternary Cu2MSnS4 (M = Cd(2+), Mn(2+)) nanocrystals.

Pressurized Organic Solvent Extraction with On-line Particle Formation by Supercritical Anti Solvent Processes

In this work, anovel on-line process for pressurised hot organic solvent extraction of antio xidants from plantsas well as precip itation of the extract with or without a carrier material in one step was developed. This process has been called OEPO,Organic solvent Ext raction and On-line particle formation. With this process, different products with a very low residual organic solvent concentration (< 50 ppm) can be obtained by the use of supercritical CO2 as anti solvent for solvent elimination.OEPO process consists of hyphenated Pressurized Liquid Extraction (PLE)-Supercritical Anti So lvent (SAS) precipitation, PLE-SAS co-p recipitat ion and PLE-Supercritical Fluid Ext raction of Emulsions (SFEE). OEPO process was successfully developed using Brazilian g inseng roots (Pfa ffiaglomerata)as a model case using ethyl acetate as extracting solvent. Results were co mpared, in terms of antio xidant activity o r mo rphology, with the ones obtained by each process separately.In addition, an optimizat ion study for antio xidants recovery was performed using ethyl acetate as extracting solvent during PLE process. Optimu m PLE extracts were produced under moderate extraction temperature (373 K) and high static extraction t ime (15 min). Under this condition an ext raction yield o f 1% (d ry basis, d.b.) and an antioxidant activity of 53% are obtained, wh ich was appro ximately 14% higherthan that observed after PLE-SAS p recipitation and after SAS precipitation performed in two steps (step one - PLE ext raction; step two - SAS precipitation by the use of the ext ract solution produced by step one stored).Similar behavior (hyphenated process producing similar p roducts than the two step process done separately) was observed for PLE-SAS co-precip itation and PLE-SFEE indicating that the OEPO process developed in this work can be considered as a suitable and p ro mising process to obtain, in only one step, different products (precipitated extract, co-precipitated extract or encapsulated extract in suspension), direct ly fro m plant materials.

Rapid SFLS Synthesis of Si Nanowires Using Trisilane with In situ Alkyl-Amine Passivation

A high-throughput synthesis of crystalline silicon nanowires is reported using trisilane as a reactant with colloidal gold nanocrystals in a hot organic solvent. Nearly 80 mg of nanowire product is obtained in a 1 min reaction from a 10 mL reactor volume. Dodecylamine surface passivation is also demonstrated.

Heteroepitaxial Growth of Colloidal Nanocrystals onto Substrate Films via Hot-Injection Routes

Hot-injection synthesis of colloidal nanocrystals (NCs) in a substrate-bound form is demonstrated. We show that polycrystalline films submerged into hot organic solvents can nucleate the heteroepitaxial growth of semiconductor NCs, for which the ensuing lattice quality and size distribution are on the par with those of isolated colloidal nanoparticles. This strategy is demonstrated by growing lead chalcogenide NCs directly onto solvent-submerged TiO(2) substrates. The resulting PbX/TiO(2) (X = S, Se, Te) nanocomposites exhibit heteroepitaxial interfaces between lead chalcogenide and oxide domains and show an efficient separation of photoinduced charges, deployable for light-harvesting applications. The extendibility of the present method to other material systems was demonstrated through the synthesis of CdS/TiO(2) and Cu(2)S/TiO(2) heterostructures, fabricated from PbS/TiO(2) composites via cation exchange. The photovoltaic performance of nanocrystal/substrate composites comprising PbS NCs was evaluated by incorporating PbS/TiO(2) films into prototype solar cells.

Facile thermolysis synthesis of CuInS2 nanocrystals with tunable anisotropic shape and structure

Monodisperse CuInS(2) nanocrystals are produced by injecting mixed metal-oleate precursors into hot organic solvents containing the dissolved sulphur sources. A better understanding of the formation mechanism of CuInS(2) has enabled us to tailor anisotropic shapes in the form of triangular-pyramid, circular cone, and bullet-like rods with tunable crystal phases by varying the synthetic conditions.

Synthesis of Ternary CuInS2 Nanocrystals; Phase Determination by Complex Ligand Species

Colloidal CuInS2 nanocrystals were synthesized in a hot organic solvent containing surfactant molecules. The CuInS2 phase was controlled by the ligand species of the metallic monomers. When the metallic monomers were coordinated with trioctylphosphite, the resulting CuInS2 had a chalcopyrite or zincblende phase. When the metallic monomers were coordinated with hexadecylamine or oleylamine, the thermodynamically metastable wurtzite phase appeared. The experimental results indicated that the obtained phase was predominantly determined by the growth rate of the nanocrystals. The bond strength between the metallic monomers and ligand molecules and steric size of the ligand molecules influenced the growth rate. The CuInS2 nanocrystals showed photoluminescence in the near-infrared region. Its energy was far from the optical energy band gap; the luminescence was attributable to the electron−hole recombination via deep defect levels. In the photoluminescence spectrum of the CuInS2/ZnS core/shell nanocrystals, a b...

Single‐Crystalline and Near‐Monodispersed NaMF3 (M: Mn, Co, Ni, Mg) and LiMAlF6 (M: Ca, Sr) Nanocrystals from Cothermolysis of Multiple Trifluoroacetates in Solution.

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Structural and morphological investigation of magnetic nanoparticles based on iron oxides for biomedical applications

The present work reports the synthesis, characterization and properties of magnetic iron oxide nanoparticles for biomedical applications, correlating the nanoscale tunabilities in terms of size, structure, and magnetism. Magnetic nanoparticles in different conditions were prepared through thermal decomposition of Fe(acac)3 in the presence of 1,2 hexadecanodiol (reducing agent) and oleic acid and oleylamine (ligands) in a hot organic solvent. The 2,3-dimercaptosuccinic acid (DMSA) was exchanged onto the nanocrystal surface making the particles stable in water. Nanoparticles were characterized by X-ray diffraction (XRD) measurements, small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Preliminary tests of incorporation of these nanoparticles in cells and their magnetic resonance image (MRI) were also carried out. The magnetization characterizations were made by isothermal magnetic measurements.

A Fabrication Method of Organic Nanocrystals Using Stabilizer-Free Emulsion

We report a novel method of producing monodispersed polycyclic aromatic hydrocarbon nanocrystals as a result of crystal growth in a stabilizer-free oil-in-water emulsion. The emulsion was prepared by dispersing a hot organic solvent including target molecules into an aqueous medium at the same temperature as the solvent, and nucleation and crystal growth were then induced in the emulsion by decreasing the temperature. The emulsifier of the organic solvents was easily removed from the dispersion medium, and we were able to obtain π-conjugated organic nanocrystals such as tetracene, C60 fullerene, and anthracene at high dispersion concentrations.

Anisotropic growth of luminescentEu3+- orEr3+-dopedGd2O3 nanocrystals

Rare-earth- (Eu3+- or Er3+-)doped Gd2O3 nanocrystals were prepared using hot solution chemistry. The growth reaction proceeds as a result of thepyrolysis of Gd3+/Eu3+ oleate complexes in a hot organic solvent mixture. Nanocrystals ofGd2O3, regardless of the rare earth activator, exhibited an anisotropic two-dimensional growth, leadingto square-shaped nanoplates with 11–16 nm edge length and 1.05 nm edge thickness. TheGd2O3 nanoplates were found to crystallize as a metastable monoclinic phase based upon x-ray diffractionand Eu3+ 5D0–7F2 transition photoluminescence emission data.Gd2O3:Er nanocrystals thatshow the characteristic Er3+ near infrared emissions at 1450–1650 nm due to4I13/2–4I15/2 transition are also reported.

Hydrolysis and silanization of the hydrosilicon surface of freshly prepared porous silicon by an amine catalytic reaction

A novel catalytic reaction using a trace of organic amine as the catalyst enables hydrolysis of the silicon–hydrogen groups on the fresh prepared porous silicon (PS), generating the hydroxyl-terminated surfaces without extensive oxidation of the Si–Si backbonds. The reactivity of the hydroxyl-terminated surfaces with various silanization reagents was investigated, which proceeds by abstraction of the surface –OH to form an organic monolayer of Si–O–Si–C bonds and importantly retains the intrinsic structural properties of the PS layers. Furthermore, an in situ silanization modification of the silicon–hydrogen surfaces has been established. Stability testing shows that the resulting organic monolayers are densely packed and are shown to be highly stable under a variety of conditions including hot water, hot organic solvent, acid, and base, but can be removed by a HF rinse.