Skin is a complex active open system composed of highly anisotropic and inhomogeneous composite materials. Additionally, the skin actively transfers heat and mass between the body and its surroundings.
Due to this complexity, a physical skin model substrate frequently tries to provide outcomes comparable to those of human skin while being significant simplifications that do not accurately represent the structure and makeup of actual skin. It is possible to create physical skin models using various materials, structures, and morphologies.
Liquid Suspensions
For replicating the optical characteristics of tissues, various liquid solutions have been utilized. Somewhat implicitly, the skin’s scattering and absorbing qualities are simulated. To achieve scattering qualities akin to skin, suspensions of lipid, polymeric, and inorganic particles can be added to liquids like water, milk, or oils.
Some popular scatterers include lipid solutions, mono-dispersed polystyrene, and titanium dioxide particles. Tests of measuring systems and theoretical models can be conducted using liquid skin models because of their high reproducibility.
Metals
Most systems to test the thermal characteristics of clothes use metal-based skin models that heavily rely on the system’s overall architecture. Their high-temperature reactivity, stable characteristics, robustness, and the availability of technology to generate a variety of shapes are the key advantages of a skin model substrate.
These systems’ primary areas of interest include material testing and development, body monitoring systems, and human body thermophysiological response. Skin temperature, sweating rate, and heat transfer are essential characteristics that these models simulate.
Epoxy Resin
Epoxy resins are necessary to create cross-linked or thermoset polymers with various characteristics. Epoxy resins’ features vary depending on the resin type and can be modified by combining them with other substances, such as plasticizers and diluents.
Epoxy resins are a good choice for thermal skin models or skin-simulant temperature sensor models for predicting skin burns because they have a thermal diffusivity near that of human skin. Epoxy resin-based human skin models are used for near-infrared calibration, optical tomography validation, and calibration of Raman instruments.
Textiles
The mechanical and frictional contact behaviour of skin can also be mimicked by synthetic and natural leathers like chamois and Lorica. Pre-wetted textile skin, textile skin with water delivered by sweating nozzles, and waterproof textile skin that is vapour permeable are the three primary categories of sweating textile-based skin models.
Investigations on the movement of liquid and water vapour, thermal insulation, and their combined effects on garment systems’ comfort and protective qualities are done using textile skin models. The textiles’ primary purpose is connected to the redistribution and transmission of moisture, and they are placed over thermo-physiological equipment and firmly fitted.
It is anticipated that the development of skin model substrate that more accurately replicate a growing number of skin properties and functions and are thus appropriate and valid for a broader range of conditions and applications will be stimulated by the advancement of new technologies and numerical simulation methods.
Final Thoughts
Such systems would simulate skin behaviour in reaction to environmental factors more accurately and, as a result, better account for changes. These characteristics brought on by physiological and regulatory processes in objective measurements.