Pulse electrochemical method for porosification of silicon and preparation of porSi powder with controllable particles size distribution

Bychto, Leszek; Chirvony, Vladimir S.; Matveeva, Eugenia

doi:10.1002/pssc.200780128

Cited by 7 publications

(6 citation statements)

References 10 publications

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“…MS-MPs were obtained by an electrochemical method similar to that previously described by us ( Pastor et al, 2009 ). The main difference was the use of a 1:1 HF:Ethanol electrolyte, and special cyclic regimes with etch-stops in order to improve the homogeneity of pore sizes distribution along with the in-depth etching ( Bychto et al, 2008 ). A constant current step (40 or 60 mA/cm 2 for 5–10 s) was followed by an etch-stop step (no current applied for 2–5 s) in cyclic periods.…”

Section: Methodsmentioning

confidence: 99%

Pore size is a critical parameter for obtaining sustained protein release from electrochemically synthesized mesoporous silicon microparticles

Pastor¹,

Reguera-Nuñez

Matveeva³

et al. 2015

PeerJ

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Mesoporous silicon has become a material of high interest for drug delivery due to its outstanding internal surface area and inherent biodegradability. We have previously reported the preparation of mesoporous silicon microparticles (MS-MPs) synthesized by an advantageous electrochemical method, and showed that due to their inner structure they can adsorb proteins in amounts exceeding the mass of the carrier itself. Protein release from these MS-MPs showed low burst effect and fast delivery kinetics with complete release in a few hours. In this work, we explored if tailoring the size of the inner pores of the particles would retard the protein release process. To address this hypothesis, three new MS-MPs prototypes were prepared by electrochemical synthesis, and the resulting carriers were characterized for morphology, particle size, and pore structure. All MS-MP prototypes had 90 µm mean particle size, but depending on the current density applied for synthesis, pore size changed between 5 and 13 nm. The model protein α-chymotrypsinogen was loaded into MS-MPs by adsorption and solvent evaporation. In the subsequent release experiments, no burst release of the protein was detected for any prototype. However, prototypes with larger pores (>10 nm) reached 100% release in 24–48 h, whereas prototypes with small mesopores (<6 nm) still retained most of their cargo after 96 h. MS-MPs with ∼6 nm pores were loaded with the osteogenic factor BMP7, and sustained release of this protein for up to two weeks was achieved. In conclusion, our results confirm that tailoring pore size can modify protein release from MS-MPs, and that prototypes with potential therapeutic utility for regional delivery of osteogenic factors can be prepared by convenient techniques.

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Section: Methodsmentioning

confidence: 99%

Pore size is a critical parameter for obtaining sustained protein release from electrochemically synthesized mesoporous silicon microparticles

Pastor¹,

Reguera-Nuñez

Matveeva³

et al. 2015

PeerJ

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“…This method is simple but has a dramatically low output. To meet the huge demand of nanostructured silicon, a growing number of research teams are active to find new strategies and develop high-output batch processing capable of producing nanostructured silicon powder in quantities allowing upscaling to industrial demands [ 16 - 18 ]. So far, a low-cost and scalable method of silicon nanowire production remains a major challenge.…”

Section: Introductionmentioning

confidence: 99%

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

et al. 2014

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In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films.

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“…Under (beneath) each surface cell a tubular layered structure appeared. As we proposed in [4] it could be the path by which the H 2 gas escaped from the grown porous film. The layered films obtained under the three pulse regime are extremely fragile.…”

Section: Experimental Results -Some Examples Of Primary Prototypes Obmentioning

confidence: 97%

“…Recently we have proposed and studied the new three pulses Regime IV [4]. It uses the advantages of an etch stop period combining them with incomplete lift-up.…”

Section: The Overview Of the Electrochemical Regimesmentioning

confidence: 99%

“…The two forms of nanostructured primary nano-Si prototypes can be easily made by the electrochemical method. Using a novel cyclic three-pulse electrochemical regime presented in this work many, important parameters like porosity, pore diameter, thickness of the layer and their numbers can be controlled by simple electrical means [3,4 ]. At the moment the only material processed by this method has been monocrystalline silicon (wafer) but there are indications that the compacted pressed polycrystalline Si tablets might be treated as well [5].…”

Section: Introductionmentioning

confidence: 99%

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A Three Pulse Electrochemical Regime as a Fabrication Platform for Nano-structured Multifunctional Silicon Based Materials and Their Primary Prototypes

Matveeva¹,

Makushok²,

Bichto³

et al. 2008

ECS Trans.

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Nano-Silicon is an extremely versatile material that can be structured at the level of its porosity, multi-film thicknesses or size of particles. Science's keen interest in these new nanomaterials is motivated by new fascinating properties and their tunability. Different forms of nano-Si primary prototypes can be made using a novel cyclic three-pulse electrochemical regime presented in this work. It consists of three pulses of different intensity: a working pulse when layer with determined thickness and porosity is formed; a cut pulse that introduces an embedded pre-partition between the layers; and an etch stop pulse when electrolyte is refreshed. An easy control by electrical means of overall morphology opens the possibility for large variations of nano-structuring in the obtained material. In-situ deposition of some metals simultaneously with layers formation through variation of the electrolyte composition and some parameters of the electrical regime is attainable as well.

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Pulse electrochemical method for porosification of silicon and preparation of porSi powder with controllable particles size distribution

Cited by 7 publications

References 10 publications

Pore size is a critical parameter for obtaining sustained protein release from electrochemically synthesized mesoporous silicon microparticles

Pore size is a critical parameter for obtaining sustained protein release from electrochemically synthesized mesoporous silicon microparticles

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

A Three Pulse Electrochemical Regime as a Fabrication Platform for Nano-structured Multifunctional Silicon Based Materials and Their Primary Prototypes

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