[Breakthrough]Xi’an Jiaotong University has made new achievements in the field of flexible device mechanical structure design and intelligent flexible sensing

In recent years, with the prevalence of major diseases and the improvement of public health concepts, wearable health monitoring has gradually emerged. Human skin strain is an important indicator of wearable health monitoring, which can reflect human health information in an all-round way. However, due to the large difference (two orders of magnitude) of skin deformation amplitudes in different parts of the human body, it is particularly important to develop a wide-area strain sensor with a wide detection range.

Based on the idea of ‚Äč‚Äčmechanical structure design of flexible devices, researchers from Xi’an Jiaotong University’s Institute of Biomimetic Engineering and Biomechanics (BEBC) have developed a stretchable biomimetic overlay scale inspired by the overlapping and overlapping scales on the snake’s body that can slide to conform to deformation. structure. Usually, the fracture and damage of rigid materials under deformation is a problem that needs to be avoided in the development of flexible devices. However, the scale structure is “the opposite”. The relative sliding between adjacent overlapping scales is used to comply with external deformation, which significantly reduces the strain on the rigid scale itself, thereby improving the ductility of the structure (over 100% strain).

Taking the conductive polymer PEDOT:PSS as an example, the researchers used the overall resistance change caused by the sliding of PEDOT:PSS scales under deformation to realize strain sensing. The detection range and sensitivity of the sensor can be flexibly adjusted by changing the pre-stretching amplitude of the substrate. High sensitivity, wide range (1%~100%) strain sensing, compared with the existing research results, the strain sensing range is significantly broadened, and the sensor is further attached to different parts of the human body surface, realizing the normal physiological activities of the human body ( Effective sensing of skin strains of different magnitudes generated by pulse, vocalization, swallowing, facial expressions, limb movements, etc., shows the potential for wearable physical movement monitoring and psychological state assessment.

The research results were published in the sister journal Cell, “Harnessing the wide-range strain sensitivity of bilayered PEDOT: PSS films for wearable health monitoring” (Harnessing the wide-range strain sensitivity of bilayered PEDOT: PSS films for wearable health monitoring). Matter, the top journal in the field of international materials. The first author of the paper is BEBC Liu Hao Distinguished Researcher, BEBC Professor Xu Feng, Hong Kong University Assistant Professor Zhang Shiming and UCLA Professor Ali Khademhosseini are the co-corresponding authors, and Xi’an Jiaotong University is the first unit and communication unit of the paper. The research achievement is BEBC’s successful development of embedded three-dimensional helical sensing structures (Small. 2018, 14, 1801711), stiffness spatially regulated hydrogel materials (Mater. Horiz. 2020, 7, 203-213), room temperature forming conductive polymerization Another important achievement in the fields of soft matter mechanics and intelligent flexible sensing has been achieved after the development of physical and hydrogel materials (Adv. Mater. progress.

The Bionic Engineering and Biomechanics Center (BEBC) of Xi’an Jiaotong University, starting from the theoretical systems of biomechanics, bioheat transfer, and biomedicine, and relying on related cutting-edge biotechnologies such as tissue engineering and cell printing, focuses on solving biomedical engineering. basic research and the design and optimization of clinical medical treatment programs.

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