Clinic Sciences Department, Medicine and Health Sciences Faculty, University of Barcelona, 08080 Barcelona, Spain.
Nursing Department, Medicine and Health Sciences Faculty, Universidad Complutense de Madrid, 28080 Madrid, Spain.
Sensors (Basel). 2024 May 4;24(9):2928. doi: 10.3390/s24092928.
The choice of materials for covering plantar orthoses or wearable insoles is often based on their hardness, breathability, and moisture absorption capacity, although more due to professional preference than clear scientific criteria. An analysis of the thermal response to the use of these materials would provide information about their behavior; hence, the objective of this study was to assess the temperature of three lining materials with different characteristics.
The temperature of three materials for covering plantar orthoses was analyzed in a sample of 36 subjects (15 men and 21 women, aged 24.6 ± 8.2 years, mass 67.1 ± 13.6 kg, and height 1.7 ± 0.09 m). Temperature was measured before and after 3 h of use in clinical activities, using a polyethylene foam copolymer (PE), ethylene vinyl acetate (EVA), and PE-EVA copolymer foam insole with the use of a FLIR E60BX thermal camera.
In the PE copolymer (material 1), temperature increases between 1.07 and 1.85 °C were found after activity, with these differences being statistically significant in all regions of interest ( < 0.001), except for the first toe (0.36 °C, = 0.170). In the EVA foam (material 2) and the expansive foam of the PE-EVA copolymer (material 3), the temperatures were also significantly higher in all analyzed areas ( < 0.001), ranging between 1.49 and 2.73 °C for EVA and 0.58 and 2.16 °C for PE-EVA. The PE copolymer experienced lower overall overheating, and the area of the fifth metatarsal head underwent the greatest temperature increase, regardless of the material analyzed.
PE foam lining materials, with lower density or an open-cell structure, would be preferred for controlling temperature rise in the lining/footbed interface and providing better thermal comfort for users. The area of the first toe was found to be the least overheated, while the fifth metatarsal head increased the most in temperature. This should be considered in the design of new wearables to avoid excessive temperatures due to the lining materials.
用于覆盖足底矫形器或可穿戴鞋垫的材料的选择通常基于其硬度、透气性和吸湿性，尽管更多的是基于专业偏好，而不是明确的科学标准。对这些材料的热响应进行分析可以提供关于它们的行为的信息；因此，本研究的目的是评估三种具有不同特性的衬里材料的温度。
在 36 名受试者（15 名男性和 21 名女性，年龄 24.6 ± 8.2 岁，体重 67.1 ± 13.6 公斤，身高 1.7 ± 0.09 米）的样本中分析了三种覆盖足底矫形器的材料的温度。使用 FLIR E60BX 热像仪，在临床活动 3 小时前后，分别使用聚乙烯泡沫共聚物（PE）、乙烯-醋酸乙烯酯（EVA）和 PE-EVA 共聚物泡沫鞋垫测量温度。
在 PE 共聚物（材料 1）中，活动后发现温度升高 1.07 至 1.85°C，除了第一脚趾（0.36°C， = 0.170）外，所有感兴趣区域的差异均具有统计学意义（ < 0.001）。在 EVA 泡沫（材料 2）和 PE-EVA 共聚物的膨胀泡沫（材料 3）中，所有分析区域的温度也显著升高（ < 0.001），EVA 的范围在 1.49 至 2.73°C 之间，PE-EVA 的范围在 0.58 至 2.16°C 之间。PE 共聚物的整体过热程度较低，无论分析的材料如何，第五跖骨头区域的温度升高最大。
对于控制衬里/鞋垫界面的温升并为使用者提供更好的热舒适性，具有较低密度或开孔结构的 PE 泡沫衬里材料将是首选。第一脚趾的区域被发现是过热最少的，而第五跖骨的头部温度升高最多。在设计新的可穿戴设备时，应考虑这一点，以避免由于衬里材料导致的过热。
