Polymers with electrically charged internal air cavities (ferroelectrets) reveal a pronounced piezoelectric response and are regarded as soft electroactive multi-functional materials. This work presents preliminary results on the preparation and piezoelectric effect of ferroelectrets based on the polylactic acid (PLA) polymer. A distinctive feature of the manufactured films is that they are biodegradable. After a microstructure modification of carbon dioxide (CO2) foamed PLA sheets by hot-pressing treatment and corona polarization, these cellular films reveal large piezoelectric d 33 and d 31 responses in both quasi-static and dynamic modes. For freshly charged films, the maximum quasi-static piezoelectric coefficients are about 600 pC/N ( d 33) and 44 pC/N ( d 31) for a relatively thick film of 360 μm and a nominal porosity of about 60%. During the first 20 days after polarization, the piezoelectric activity decreases by half compared to the primary value, but then remains almost unchanged for a long time. Due to an already established inherent biocompatibility of PLA polymers, these eco-friendly ferroelectrets can be potentially used in various biological applications such as biosensors and microenergy harvesters embedded in tissue and artificial muscles.

中文翻译：

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具有强纵向和横向压电性的可生物降解细胞聚乳酸铁驻极体

具有带电内部空气腔（铁电驻极体）的聚合物显示出明显的压电响应，被视为软电活性多功能材料。这项工作展示了基于聚乳酸 (PLA) 聚合物的铁驻极体的制备和压电效应的初步结果。制造的薄膜的一个显着特点是它们是可生物降解的。通过热压处理和电晕极化对二氧化碳 (CO2) 泡沫 PLA 片材进行微结构改性后，这些蜂窝状薄膜在准静态和动态模式下均显示出大的压电 d 33 和 d 31 响应。对于新鲜充电的薄膜，对于 360 μm 的较厚薄膜和约 60% 的标称孔隙率，最大准静态压电系数约为 600 pC/N (d 33) 和 44 pC/N (d 31)。在极化后的前 20 天内，压电活动与初始值相比降低了一半，但随后很长一段时间内几乎保持不变。由于 PLA 聚合物固有的生物相容性，这些环保的铁电驻极体可用于各种生物应用，例如嵌入组织和人造肌肉中的生物传感器和微能量收集器。