Biocompatible organic coating fabrication via polymer/clay nanocomposites: Evaluation of mechanical improvements

Abstract This study focuses on achieving mechanical enhancements in biocompatible organic coatings. A solvent‐based method is employed to produce biocompatible nanocomposites using polyvinylpyrrolidone (PVP) and bentonite nanoclays (BNT) as constituents to achieve this objective. Subsequently, the nanocomposites are spin‐coated onto a glass substrate, resulting in smooth and defect‐free films with a thickness of 5 μm. Through instrumented‐indentation testing, it is observed that BNT reinforcement leads to significant improvements in mechanical properties. Specifically, the addition of 0.5, 1, and 5 wt% of BNT in PVP results in enhancements of 105%, 77%, and 430% in elastic modulus, respectively, while hardness is improved by 166%, 211%, and 448%, respectively. The considerable improvements in the composite modulus cannot be adequately explained by assuming perfect adhesion between the constituents of the composite (as suggested by the Halpin–Tsai model) or by considering the contributions from the interface/network of silicate layers (as proposed by the Modified Halpin–Tsai model). Instead, the significant enhancements in hardness and modulus values are primarily attributed to a notable increase in the BNT volume fraction, ranging from 4 to 9 times, occurring under the Berkovich tip due to the aggregated silicate layers. The findings highlight the role of aggregated silicate layers in enhancing both hardness and modulus and contribute to the development of advanced biocompatible coatings with improved mechanical properties. Highlights Enhanced mechanical properties in biocompatible coatings. Biocompatible nanocomposites of polyvinylpyrrolidone (PVP) and bentonite nanoclays (BNT). Spin‐coated nanocomposite films on glass: smooth, defect‐free, 5 μm thick. BNT reinforcement boosts elastic modulus and hardness of PVP. Aggregated silicate layers under compression drive substantial mechanical improvements.