Loading antifungal drugs onto silica particles grafted with cyclodextrins by means of inclusion complex formation at the solid surface

International audienc

Silica particles with grafted UV-filter for the stabilization of pickering emulsions

International audiencePickering emulsions have been prepared using silica particles grafted with UV-filter as stabilizers. Such formulation contains all the ingredients of a sun protection product: organic UV-filter, inorganic particles as anti-UV screen and oil. Grafting the UV-filter is expected to prevent deep penetration of potentially harmful organic molecules inside the skin. p-methoxycinnamate has been immobilized onto to the surface of fumed silica particles. The UV-filter molecule was attached to silica by means of a short (C2) or a long (C10) alkyl spacer to study their effect on grafting degree. Better water dispersion was obtained for the two materials. The water dispersion particles remained stable for 40 days. The hydrophobically-modified silica, with different grafting degrees and linkers, were used for the formulation of o/w Pickering emulsions with various oils of cosmetic relevance: silicone oils of different viscosities and octylbenzoate. The stability and drop size distributions in the different emulsions are evaluated. Stable emulsions were obtained with oil contents in the range 10% to 60%. UV-absorbing ability was retained after immobilization of UV-filter molecules onto silica particles in all emulsion

Low-cost Posidonia oceanica bio-adsorbent for efficient removal of antibiotic oxytetracycline from water

International audienc

Silica particles with grafted UV-filter for the stabilization of pickering emulsions

International audiencePickering emulsions have been prepared using silica particles grafted with UV-filter as stabilizers. Such formulation contains all the ingredients of a sun protection product: organic UV-filter, inorganic particles as anti-UV screen and oil. Grafting the UV-filter is expected to prevent deep penetration of potentially harmful organic molecules inside the skin. p-methoxycinnamate has been immobilized onto to the surface of fumed silica particles. The UV-filter molecule was attached to silica by means of a short (C2) or a long (C10) alkyl spacer to study their effect on grafting degree. Better water dispersion was obtained for the two materials. The water dispersion particles remained stable for 40 days. The hydrophobically-modified silica, with different grafting degrees and linkers, were used for the formulation of o/w Pickering emulsions with various oils of cosmetic relevance: silicone oils of different viscosities and octylbenzoate. The stability and drop size distributions in the different emulsions are evaluated. Stable emulsions were obtained with oil contents in the range 10% to 60%. UV-absorbing ability was retained after immobilization of UV-filter molecules onto silica particles in all emulsion

Design of molecularly imprinted polymer materials relying on hydrophobic interactions

International audienc

Pickering emulsion polymerization of polyaniline/LiCoO2 nanoparticles used as cathode materials for lithium batteries

International audienc

ZnS quantum dots as fluorescence sensor for quantitative detection of tetracycline

International audienceX–ZnS quantum dots (QDs) are synthesized in aqueous solution by a simple aqueous chemical route where X represents 3-mercaptopropionic acid (MPA) or 3-mercapto-1-propanesulfonic acid (MPS) which are two well-known low cost and stable ligands. The synthesized X–ZnS QDs yielded aqueous suspensions of nanoparticles with excellent monodispersity, water solubility and fluorescence stability with a relatively high fluorescence quantum yield of 11% and 10% for MPA-ZnS QDs and MPS-ZnS QDs respectively. Under optimal conditions, the prepared X–ZnS QDs are used to detect tetracycline (TC) based on their fluorescence quenching induced by the target analyte via electrostatic interaction. The Stern–Volmer-type equation has been fitted to the quenching curve of each QDs, from which MPA-ZnS QDs has shown a larger linear range and a lower limit of detection than MPS-ZnS QDs. The fluorescence response of MPA-ZnS QDs is linearly with respect to TC concentration over a wide range from 200 nM to 6000 nM with a detection limit of 30 pM. The combination of non-toxicity, simplicity and low cost together with high analytical performance of the proposed MPA-ZnS QDs make it promising for the determination of trace TC in food products of animal origin

Structural and electrochemical characterization of polyaniline/LiCoO2 nanocomposites prepared via a Pickering emulsion

International audiencePolyaniline (PANI)/LiCoO2 nanocomposite materials are successfully ready through a solid-stabilized emulsion (Pickering emulsion) route. The properties of nanocomposite materials have been put to the test because of their possible relevance to electrodes of lithium batteries. Such nanocomposite materials appear thanks to the polymerization of aniline in Pickering emulsion stabilized with LiCoO2 particles. PANI has been produced through oxidative polymerization of aniline and ammonium persulfate in HCl solution. The nanocomposite materials of PANI/LiCoO2 could be formed with low amounts of PANI. The morphology of PANI/LiCoO2 nanocomposite materials shows nanofibers and round-shape-like morphology. It was found that the morphology of the resulting nanocomposites depended on the amount of LiCoO2 used in the reaction system. Ammonium persulfate caused the loss of lithium from LiCoO2 when it was used at high concentration in the polymerization recipe. Highly resolved splitting of 006/102 and 108/110 peaks in the XRD pattern provide evidence to well-ordered layered structure of the PANI/LiCoO2 nanocomposite materials with high LiCoO2 content. The ratios of the intensities of 003 and 104 peaks were found to be higher than 1.2 indicating no pronounced mixing of the lithium and cobalt cations. The electrochemical reactivity of PANI/LiCoO2 nanocomposites as positive electrode in a lithium battery was examined during lithium ion deinsertion and insertion by galvanostatic charge–discharge testing; PANI/LiCoO2 nanocomposite materials exhibited better electrochemical performance by increasing the reaction reversibility and capacity compared to that of the pristine LiCoO2 cathode. The best advancement has been observed for the PANI/LiCoO2 nanocomposite 5 wt.% of aniline

Molecularly imprinted polyaniline on silica support for the selective adsorption of benzophenone-4 from aqueous media

International audienc