Coatings

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Open AccessArticle

Physicochemical, Microstructural and Biological Evaluation of Dressing Materials Made of Chitosan with Different Molecular Weights

by Zofia Płonkowska, Alicja Wójcik and Vladyslav Vivcharenko

Coatings 2025, 15(10), 1116; https://doi.org/10.3390/coatings15101116 (registering DOI) - 24 Sep 2025

Abstract

The use of advanced wound dressings can significantly support the skin healing process by maintaining optimal conditions for tissue regeneration. In this study, foam-like dressings composed of agarose and chitosan, enriched with vitamin C, were developed using a simple and cost-effective freeze-drying method. Three types of chitosan with varying molecular weights (low, medium, high) were used to investigate their impact on the biological, physicochemical, and mechanical properties of the resulting foams. All fabricated biomaterials were biocompatible, non-toxic, and did not promote cell adhesion to their surfaces. The foams exhibited highly porous, hydrophilic microstructures with excellent fluid absorption capacity (~20 mL/g) and sustained vitamin C release over the first 24 h. Chitosan molecular weight had no significant effect on biological properties, but influenced samples’ wettability and mechanical parameters. The hydrophilic character of samples was observed in all tested biomaterials, with the strongest enhancement of hydrophilicity noted for the low molecular weight variant. The highest tensile strength was observed in samples prepared with medium molecular weight chitosan. The results indicate that among the analyzed variants, agarose-chitosan foam biomaterials containing medium molecular weight chitosan exhibited the most favorable properties, making them the most promising candidates for the treatment of wounds with excessive exudate. Full article

(This article belongs to the Special Issue Advanced Biomaterials, Coatings and Techniques: Applications in Medicine and Dentistry, 2nd Edition)

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20 pages, 8912 KB

Open AccessArticle

Experimental Study on Tool Performance in the Machining of AISI 4130 Alloy Steel with Variations in Tool Angle and Cutting Parameters

by Jinxing Wu, Yi Zhang, Wenhao Hu, Changcheng Wu, Zuode Yang and Ruobing Yang

Coatings 2025, 15(10), 1115; https://doi.org/10.3390/coatings15101115 - 23 Sep 2025

Abstract

The high hardness and toughness of AISI 4130 alloy present significant challenges during machining, including excessive cutting forces, rapid tool wear, and poor surface finish control. To address these issues, this study combines numerical simulation with turning experiments to systematically investigate the effects of tool geometry and cutting parameters on cutting force, temperature, and surface roughness. Through Deform-3D finite element modeling, one-factor, and orthogonal simulation tests, it was found that the optimal tool geometric combination (λs = 2°, κ_r = 99°, γ₀ = 5°) reduces the cutting forces by 21.86% as compared to the baseline parameters. Experimental validation showed that the agreement between simulated and measured cutting forces was 86.73%–87.8%, with simulated values being 10%–13.27% higher due to idealized boundary conditions. Surface morphological analysis by Bruker Contour Elite K shows that the surface roughness of the workpiece decreases with an increasing cutting speed and increases with an increasing feed rate and depth of cut. The above studies provide a certain research basis for optimizing the tool angle and improving the cutting efficiency. Full article

(This article belongs to the Special Issue Alloy/Metal/Steel Surface: Fabrication, Structure, and Corrosion)

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19 pages, 6535 KB

Open AccessArticle

SEM/EDS and Roughness Analysis on Current Titanium Implant Decontamination Systems: In Vitro Study

by Marco Lattari, Andrea Butera, Simone Roatti, Maurizio Pascadopoli, Beatrice Alberti, Saverio Cosola, Mario Alovisi and Andrea Scribante

Coatings 2025, 15(10), 1114; https://doi.org/10.3390/coatings15101114 (registering DOI) - 23 Sep 2025

Abstract

The aim of this study was to evaluate the effects of different decontamination treatments on the surface roughness and elemental deposition of pristine dental implants using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). We divided 110 dental implants into 21 groups based on the decontamination method used in vitro. One group was the untreated control. Roughness values (R_a) were analyzed with a profilometer, while elemental deposition was assessed through EDS. Results were obtained for each treatment and for macrogroups (control, ultrasound, curettes, powders, brushes, gels). Significantly lower R_a values were found in the neck zone with respect to the thread zone (p < 0.05). EDS analysis revealed a non-significant higher presence of carbon and calcium in certain treatments, denoting a certain deposition of the decontaminating products (p > 0.05). Although there were various significant differences among the groups, roughness values were low and no decontaminating methods macroscopically affected implant surfaces, so decontaminating procedures can be considered safe. Full article

(This article belongs to the Special Issue Surface Properties of Dental Materials and Instruments, 3rd Edition)

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Coatings, Volume 15, Issue 10 (October 2025) – 3 articles

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