Elastomeric encapsulation layers are widely used in soft, wearable devices to physically isolate rigid electronic components from external environmental stimuli(e.g., stress) and facilitate device sterilization for re...Elastomeric encapsulation layers are widely used in soft, wearable devices to physically isolate rigid electronic components from external environmental stimuli(e.g., stress) and facilitate device sterilization for reusability. In devices experiencing large deformations, the stress-isolation effect of the top encapsulation layer can eliminate the damage to the electronic components caused by external forces. However, for health monitoring and sensing applications, the strain-isolation effect of the bottom encapsulation layer can partially block the physiological signals of interest and degrade the measurement accuracy. Here, an analytic model is developed for the strain-and stress-isolation effects present in wearable devices with elastomeric encapsulation layers. The soft, elastomeric encapsulation layers and main electronic components layer are modeled as transversely isotropicelastic mediums and the strain-and stress-isolation effects are described using isolation indexes. The analysis and results show that the isolation effects strongly depend on the thickness, density, and elastic modulus of both the elastomeric encapsulation layers and the main electronic component layer. These findings, combined with the flexible mechanics design strategies of wearable devices, provide new design guidelines for future wearable devices to protect them from external forces while capturing the relevant physiological signals underneath the skin.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 12172319, 11872326, and 12072057)the Natural Science Foundation of Hunan Province (Grant Nos. 2021JJ30648, and2021JJ30641)+4 种基金the Furong Scholars Programme of Hunan Provincethe Liao Ning Revitalization Talents Program (Grant No. XLYC2007196)the Fundamental Research Funds for the Central Universities (Grant No.DUT20RC(3)032)the National Science Foundation Graduate Research Fellowship (Grant No. 1842165)the Ford Foundation Predoctoral Fellowship。
文摘Elastomeric encapsulation layers are widely used in soft, wearable devices to physically isolate rigid electronic components from external environmental stimuli(e.g., stress) and facilitate device sterilization for reusability. In devices experiencing large deformations, the stress-isolation effect of the top encapsulation layer can eliminate the damage to the electronic components caused by external forces. However, for health monitoring and sensing applications, the strain-isolation effect of the bottom encapsulation layer can partially block the physiological signals of interest and degrade the measurement accuracy. Here, an analytic model is developed for the strain-and stress-isolation effects present in wearable devices with elastomeric encapsulation layers. The soft, elastomeric encapsulation layers and main electronic components layer are modeled as transversely isotropicelastic mediums and the strain-and stress-isolation effects are described using isolation indexes. The analysis and results show that the isolation effects strongly depend on the thickness, density, and elastic modulus of both the elastomeric encapsulation layers and the main electronic component layer. These findings, combined with the flexible mechanics design strategies of wearable devices, provide new design guidelines for future wearable devices to protect them from external forces while capturing the relevant physiological signals underneath the skin.
