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International audience; Three-dimensional hydroxyapatite-chitosan (HA-CS) composites loaded with ciprofloxacin antibiotic (HA-CS-CIP) were formulated using the in situ and the solid-liquid method coupled with the freeze-drying process. The interaction of the HA-CS composite powder and ciprofloxacin antibiotic (CIP) was investigated by batch adsorption essays. The kinetic and the isotherm data were fitted well to the pseudo-second-order and Freundlich models, respectively. The compressive strength of the HA-CS composite was increased by 7-fold and 10-fold when using respectively 15 wt% and 30 wt% of the polymer compared to the HA-CS5 formulation (3.6 +/- 0.7 MPa) made only from HA powder and CS gel (5 wt%). However, this parameter decreased from 36.8 +/- 8.5 MPa down to 20.5 +/- 4.7 MPa when the antibiotic content increased from 0 up to 9 wt%, respectively. The in vitro release results showed a sustained and controlled CIP release for up to 10 days. The release data fitting and modeling indicate that the process follows a Fickian diffusion mechanism. Also, the formulated composite revealed an antibacterial effect against Staphylococcus aureus and Escherichia coli bacteria. The developed

International audience; A composite based on hydroxyapatite (HA) and chitosan (CS) combined with ciprofloxacin (CIP) was formulated by the solid-liquid mixing method. The optimization of the solid to the liquid ratio and the use of chitosan in a small amount (

This work reports on the preparation of oil-filled microcapsules for self-healing purposes. Biopolymeric microcapsules loaded with vegetable oils as green corrosion inhibitors were formulated using ethyl cellulose and phosphorylated ethyl cellulose as encapsulating materials. Chemical structure, thermal stability and surface morphology of microcapsules were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). FTIR and TGA analysis confirmed the presence of oil core and polymer shell in the formulated microcapsules. The scanning electron microscopy was used to evaluate the shape and morphology of the prepared microcapsules. The obtained results revealed the spherical-like shape of the obtained capsules with diameters ranging from 10 up to 170 µm. Thus, the current study shows the potential application of phosphorylated ethyl cellulose for the development of new environmentally friendly microcontainers bearing corrosion inhibitors for end use in anti-corrosion self-healing coatings.

This study reports for the first time the preparation of almond oil-based microcapsules using phosphorylated ethyl cellulose as shell material. Microcapsules of ethyl cellulose (EC) and phosphorylated ethyl cellulose (P-EC) containing almond oil as anti-corrosion inhibitor, for end use in self-healing coatings, were prepared by a solvent evaporation method. The results showed that phosphorus content in the modified ethyl cellulose was 6.26 wt.%, the specific surface area reached a high value of 21.4 m2 g−1 and a char residue of 18 wt.% at 400 °C after thermal degradation. Both prepared EC and P-EC based microcapsules were spherical shape-like. The scanning electron microscope (SEM) images showed that the freeze-drying influences the microcapsules surface morphology. The mean diameter of EC and P-EC microcapsules was about 140 μm and 150 μm, respectively. Anti-corrosion properties of prepared epoxy-based coatings loaded with microcapsules on the mild steel substrate were evaluated for 28 days using a simple salt spray test. The sample containing P-EC microcapsules showed the best anticorrosion resistance. The functionalization of the ethyl cellulose microcapsules shell with phosphonate groups can improve further the anti-corrosion resistance, the flame-retardant ability and the metal chelating properties of the final coatings.