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In this work, the synthesis of high-performance, metal ion-imprinted, mesoporous carbon electrocatalysts for hydrazine oxidation reaction (HzOR) using casein or a family of phosphoproteins derived from cow's milk as a precursor is shown. The synthesis is made possible by mixing trace amounts of non-noble metal ions (Fe 3+ or Co 2+ ) with casein and then producing different metal ions-functionalized casein intermediates, which upon carbonization, followed by acid treatment, lead to metal ionimprinted catalytically active sites on the materials. The materials effectively electrocatalyze HzOR with low overpotentials at neutral pH and exhibit among the highest electrocatalytic performances ever reported for carbon catalysts. Their catalytic activities are also better than the corresponding control material, synthesized by carbonization of pure casein and other materials previously reported for HzOR. This work demonstrates a novel synthetic route that transforms an inexpensive protein to highly active carbon-based electrocatalysts by modifying its surfaces with trace amounts of non-noble metals. The types of metal ions employed in the synthesis are found to dictate the electrocatalytic activities of the materials. Notably, Fe 3+ is found to be more effective than Co 2+ in helping the conversion of casein into more electrocatalytically active carbon materials for HzOR.

Ionic liquid-modified cellulose nanowhiskers are synthesized and successfully used as precursors to make heteroatom-doped carbon catalysts.

Hybrid nanostructured materials comprised amorphous carbon nanoneedles (CNN)-supported Co3O4 nanoparticles (Co3O4-CNN) were synthesized. The synthesis involved layer-by-layer nanocasting of cellulose nanowhiskers with cobalt oxide and silica precursors, followed by pyrolysis of the core-shell-shell composite materials and etching of the outer silica shells off of the carbonized materials. Notably, cotton-derived cellulose nanowhiskers were used as the carbon precursors, and also as the hard templates for needle-shaped carbons, in the synthesis. The effectiveness of the core-shell-shell nanoreactors, possessing the silica shell-entrapped cellulose nanowhiskers and Co(II) ions, in generating organized carbon nanomaterials with metal oxide nanoparticles, or otherwise, as a function of the loading of Co(II) ions was evaluated. Details of the synthetic method and the different materials in terms of composition and morphology it results in as a function of the relative amount of metal ions have also been discussed. The materials showed promising supercapacitive properties and electrocatalytic activity for oxygen reduction reaction (ORR). The materials' double layer capacitance and performance for ORR electrocatalysis as a function of their Co3O4 content and particles size have also been discussed. The results indicated that the electrochemical properties of these hybrid materials are strongly related to the morphology of their carbon nanostructures. The synthetic method demonstrated here can potentially serve as a facile route to produce other metal oxide/carbon nanomaterials, with different morphology and similar or better properties, using other carbon precursors. 16,17

An inorganic/organic hybrid material with triggering mechanism for specific drug delivery at colon is demonstrated. First, hydroxyapatite nanowhiskers (n-HA) with high aspect ratio, narrow particle size distribution and high surface area, ca. 67 m 2 /g, are prepared. As a proof-of-concept, terbinafine, a fungicidal agent, is loaded onto the n-HA, obtaining a drug loading of 40.63 mg of terbinafine per gram of n-HA. Hydroxyapatite nanowhiskers loaded with terbinafine are encapsulated with chondroitin sulfate (CS) microspheres, using chemically modified glycidyl methacrylate by performing ultrasonic microemulsion polymerization. The obtained hybrid materials were characterized by TEM, SEM, FTIR, and NMR. Dispersed n-HA in CS microspheres are obtained for different n-HA contents, from 1 to 10% (%w/w). Terbinafine release from hybrid microspheres is caried out by in vitro studies in simulated gastric fluid and simulated intestinal fluid. The studies demonstrated that sustained drug release can be obtained using the developed hybrid material.

A facile and reproducible route that can lead to two-dimensional arrays of nanopores in thin polymer films is demonstrated. The formation of the pores in the polymer films involves breath figure phenomenon and occurs during the film deposition by spin coating. The formation of nanoporous thin films takes only few seconds, and the method does not require complex equipment or expensive chemicals. This method also constitutes a straightforward approach to control the size of the pores formed in thin films. Besides allowing control over the average pore size of the porous films, the use of dynamic deposition with the breath figure phenomenon causes the reduction in the pore size to nanometer scale. The nanoporous arrays obtained by the breath figure are applied as substrates for cell growth, and the effect of their nanopore size on cell growth was evaluated. Notably, it is found that cell viability is related to pore size, where 2D nanoporous structure is more beneficial for cell culture than 2D microporous structures. The change in the average pore size of the polymer films from 1.22 μm to 346 nm results in a threefold increase in cell viability.

Inorganic/polymer composite materials with controlled phases organized in layers with part of the inorganic material hosted by a hydrophilic polymer layer covalently bound to a hydrophobic polymer layer and the other part of the inorganic material in crystalline phases adsorbed onto the composite surface were prepared. An ultrathin layer of poly(vinyl alcohol) (PVA) and a poly(acrylic acid) (PAA) layer were prepared on polyethylene films, which were used in the crystallization of CaCO3 by a sequential immersion method in a dip-coating process. The number of sequential immersions and the addition of PVA as a possible stabilizer were analyzed. The data suggest that the nucleation and growth of the inorganic material started on the hydrophilic polymer layer, which was composed mainly of PAA, and a mixed inorganic/organic layer was formed. The shape and the proportions of the CaCO3 phases on the composite surface depend on the number of immersion cycles and the addition of PVA.

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