A tribo-mechanical analysis of PVA-based building-blocks for implementation in a 2-layered skin model

• Published in: Journal of the mechanical behavior of biomedical materials 2016-09, Vol.62, p.319-332
• Main Authors: Morales Hurtado, M., de Vries, E.G., Zeng, X., van der Heide, E.
• Format: Article
• Language: English
• Subjects: 2-Layered Skin Model; Biocompatible Materials; Elastic Modulus; Friction; Humans; Hydrogels; Polyvinyl Alcohol; PVA hydrogel; Skin tribology; Skin, Artificial; Surface Properties; Tribo-mechanical properties
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2016.05.001

Poly(vinyl) alcohol hydrogel (PVA) is a well-known polymer widely used in the medical field due to its biocompatibility properties and easy manufacturing. In this work, the tribo-mechanical properties of PVA-based blocks are studied to evaluate their suitability as a part of a structure simulating the length scale dependence of human skin. Thus, blocks of pure PVA and PVA mixed with Cellulose (PVA-Cel) were synthesised via freezing/thawing cycles and their mechanical properties were determined by Dynamic Mechanical Analysis (DMA) and creep tests. The dynamic tests addressed to elastic moduli between 38 and 50kPa for the PVA and PVA-Cel, respectively. The fitting of the creep compliance tests in the SLS model confirmed the viscoelastic behaviour of the samples with retardation times of 23 and 16 seconds for the PVA and PVA-Cel, respectively. Micro indentation tests were also achieved and the results indicated elastic moduli in the same range of the dynamic tests. Specifically, values between 45–55 and 56–81kPa were obtained for the PVA and PVA-Cel samples, respectively. The tribological results indicated values of 0.55 at low forces for the PVA decreasing to 0.13 at higher forces. The PVA-Cel blocks showed lower friction even at low forces with values between 0.2 and 0.07. The implementation of these building blocks in the design of a 2-layered skin model (2LSM) is also presented in this work. The 2LSM was stamped with four different textures and their surface properties were evaluated. The hydration of the 2LSM was also evaluated with a corneometer and the results indicated a gradient of hydration comparable to the human skin. •Synthesis of PVA and PVA-Cellulose blocks is presented in the text.•The elastic moduli are in the range of the ultra-soft materials, such as human skin.•A method to produce a 2-layered skin model based on PVA building blocks is presented.•The hydration gradient was in good agreement to that between Dermis and Epidermis.•The shear strength must be increased to approach the friction performance of skin.