The importance of continuous monitoring of skin hydration in daily life, to aid in the diagnosis of skin diseases, is rising. Electrodes that can be worn directly on the skin are attracting attention as an effective means. However, they should not inhibit natural water evaporation from the skin and should not cause inflammation or irritation even if they are attached to the body for long periods of time. In this study, nanomesh electrodes that have previously been reported to exhibit high biocompatibility are also found to exhibit high water vapor permeability, resulting in properties that prevent skin dampness. Furthermore, the skin impedance measured using nanomesh electrodes is found to correlate with the hydration level of skin measured using existing medical equipment. This study provides a new approach to measure skin hydration in conditions close to bare skin. Skin is the outermost organ of the body and acts as a barrier separating the inside of the body from the outside world. Skin is essential to prevent the entry of pathogens and contaminants from the outside environment into the body, as well as to prevent excessive evaporation of water from the body. The stratum corneum, the outermost layer of the skin, serves as a barrier that inhibits water evaporation from the skin called trans-epidermal water loss (TEWL). [1] When the stratum corneum is damaged, the water in skin evaporates more easily to the outside world, making the skin prone to dryness. [2] Therefore, it is important to measure the skin hydration levels to assess the barrier function of the stratum corneum. The evaluation of the stratum corneum's barrier function has attracted significant attention from the cosmetic and medical fields as it is useful for understanding the characteristics of an individual's skin and diagnosing skin diseases such as atopic dermatitis, [3] ichthyosis vulgaris, [4] and psoriasis. [5] Skin hydration levels are commonly measured indirectly by measuring the skin's electrical properties, such as the skin impedance and skin capacitance. This is because the higher the hydration level of the skin, the higher the conductivity and dielectric constant. [6,7] In the medical community, the electrical properties of the skin are measured using probes with rigid electrodes

Thin parylene coating suppressed the negative temperature coefficient (NTC) effect of polymer thermistors with a positive temperature coefficient (PTC) while maintaining the PTC characteristics.

We have proposed and fabricated resistive-type flexible pressure sensors composed of multi-walled carbon nanotube thin films, liquid metal droplets, sponge rubber, and paper. The pressure sensor detects external pressure in the range of tens of kilopascals. The resistance change was found to be approximately 70% when a pressure of 100 kPa was applied. The sensor operation showed good reproducibility under cyclic applied pressure. The simple sensor structure and environment-friendly materials allow the sensor to be easily disassembled into its components, which are reusable and combustible.