Wettability Properties Of Films Research Articles

Effect of light on the wettability properties of films made by the assembly of SiO2 and α − Fe2O3 nanoparticles

We report an experimental study of the effect of visible and UV light irradiation on the wettability of films made by the assembly of SiO2 and α − Fe2O3 particles in the nanometer range. To optimize the conditions for the film formation (adhesion of nanoparticles on glass substrates) using a dip-coating technique, we have analyzed the colloidal stability through Zeta-potential measurements of the nanoparticles by varying the pH of the solution. Additionally, X-ray diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy were used to study the structural and optical properties of the samples. The wettability behavior was performed by contact angle (CA) measurements using a sessile drop method. The atomic force microscope (AFM) results showed similar roughness parameters for both systems; however, we have obtained different wettability characteristics: superhydrophilic for SiO2 and hydrophilic for α − Fe2O3. This difference is due to its physicochemical nature rather than the morphological structure of their surfaces, as predicted by the Wenzel equation. The CA of α − Fe2O3 surface changed upon irradiation by visible (2.7 eV) and UV (4.2 eV) light, i.e. from 38° (hydrophilic) to 15° (highly hydrophilic), respectively, while the SiO2 case was kept constant (around 7°). These changes in CA can be attributed to the amount and mechanism of electron-hole pair photogenerated that breakdown organic molecules or dissociate water from moisture, lead to increasing hydroxyl species on the surface. The present study could provide new insights to control the wettability on hydrophilic surfaces with complex structures when it is irradiated with light at different wavelengths.

Azithromycin-Chitosan Films for Improved Haemostasis and Wound Healing

Wound healing is a global medical concern, because haemorrhage is still a major cause of morbidity and mortality. Therefore, more effective and cost-effective dressings are required. Antimicrobial dressing of Azithromycin (AZM) (a broad-spectrum macrolide antibiotic) with Chitosan (CS) as a carrier, has a lot of desired properties such as haemostatic, pain-reducing, and less scar forming. It is prepared by a solvent evaporation method. The film morphology is investigated by SEM and film-water wettability is measured by a contact angle method. The drug-polymer interactions are evaluated by using FTIR and DSC. Azithromycin loaded films (different mass ratio of AZM to CS w % 10%, 25% and 50%) were sterilized by Gamma radiation, then their antimicrobial characteristics and haemostatic performance were evaluated. Film thickness was about 9 µm. The wettability properties of films were enhanced by adding AZM and PEG6000 5% (mass ratio of PEG 6000 to CS w %). Microbial growth inhibitions were identified for films loaded with Azithromycin.