Bendable Electronics and Sensing Technologies Group, James Watt School of Engineering , University of Glasgow , Glasgow G12 8QQ , United Kingdom.
ACS Appl Mater Interfaces. 2020 Feb 26;12(8):9008-9016. doi: 10.1021/acsami.9b21052. Epub 2020 Feb 14.
This paper presents flexible pressure sensors based on free-standing and biodegradable glycine-chitosan piezoelectric films. Fabricated by the self-assembly of biological molecules of glycine within a water-based chitosan solution, the piezoelectric films consist of a stable spherulite structure of β-glycine (size varying from a few millimeters to 1 cm) embedded in an amorphous chitosan polymer. The polymorphic phase of glycine crystals in chitosan, evaluated by X-ray diffraction, confirms formation of a pure ferroelectric phase of glycine (β-phase). Our results show that a simple solvent-casting method can be used to prepare a biodegradable β-glycine/chitosan-based piezoelectric film with sensitivity (∼2.82 ± 0.2 mV kPa) comparable to those of nondegradable commercial piezoelectric materials. The measured capacitance of the β-glycine/chitosan film is in the range from 0.26 to 0.12 nF at a frequency range from 100 Hz to 1 MHz, and its dielectric constant and loss factor are 7.7 and 0.18, respectively, in the high impedance range under ambient conditions. The results suggest that the glycine-chitosan composite is a promising new biobased piezoelectric material for biodegradable sensors for applications in wearable biomedical diagnostics.
本文提出了基于独立和可生物降解的甘氨酸-壳聚糖压电薄膜的柔性压力传感器。该压电薄膜通过甘氨酸生物分子在基于水的壳聚糖溶液中的自组装制造而成，由稳定的β-甘氨酸（尺寸从几毫米到 1 厘米不等）的球晶结构嵌入无定形壳聚糖聚合物中组成。通过 X 射线衍射评估甘氨酸晶体在壳聚糖中的多晶相，证实了甘氨酸（β 相）的纯铁电相的形成。我们的结果表明，可以使用简单的溶剂浇铸法制备可生物降解的β-甘氨酸/壳聚糖基压电薄膜，其灵敏度（∼2.82 ± 0.2 mV kPa）可与不可生物降解的商业压电材料相媲美。在 100 Hz 至 1 MHz 的频率范围内，β-甘氨酸/壳聚糖薄膜的电容在 0.26 到 0.12 nF 之间，在环境条件下的高阻抗范围内，其介电常数和损耗因子分别为 7.7 和 0.18。结果表明，甘氨酸-壳聚糖复合材料是一种很有前途的新型生物基压电材料，可用于可生物降解的传感器，应用于可穿戴生物医学诊断。
