离子液体掺杂左旋聚乳酸薄膜的制备及压电性能研究

Preparation and Piezoelectric Properties of Ionic Liquid-doped Poly-L-lactic Acid Films

聚L-乳酸(PLLA)不仅具有透明、柔软、绿色来源、可再生、可生物降解以及生物兼容等特点,还具有一定的剪切压电性能,是运动测量、健康监测、人机交互等领域的热点材料。然而左旋聚乳酸的压电性能较聚偏四氟乙烯(PVDF)弱。为进一步提升左旋聚乳酸薄膜的压电性能,通过少量掺杂(1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐)离子液体(IL)和后处理工艺制备了一种压电性能增强的左旋聚乳酸薄膜。采用X射线衍射、拉曼光谱、力学测试仪等设备详细研究了掺杂不同质量比IL(0%、0.25%、1%、4%)的PLLA薄膜在不同退火工艺下的结晶性能和压电特性。结果表明,PLLA薄膜的压电性能随着离子液体浓度的增加和退火时间的增加而增加;4%IL掺杂且退火2 h的PLLA/IL复合薄膜的电压响应信号达到0.64 V,是纯PLLA薄膜对照组电压响应峰值信号的2倍。因此,通过往PLLA薄膜合理掺杂IL和适当退火处理能够获得高压电性能的左旋聚乳酸薄膜。

Poly-L-lactic acid(PLLA)is transparent,flexible,green-sourced,renewable,biodegradable or biocompatible,but also has the shear piezoelectric properties,which is the topic material in the field of motion measurement,health monitoring,and human-computer interaction.However,the piezoelectric properties of PLLA are weak compared to polyvinylidene fluoride(PVDF).To further improve the piezoelectric properties of PLLA film,an enhanced PLLA film is prepared in this paper using a small amount of(1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide salt)ionic liquid(IL)and post-treatment process.The crystallization and piezoelectric properties of PLLA film doped with IL of different mass ratios(0%,0.25%,1%,4%)are investigated in detail by X-ray diffraction,Raman spectroscopy,and mechanical measurement under different annealing.The results show that the piezoelectric properties of PLLA films increase with the increase of IL concentration and annealing time;the peak voltage response signal of PLLA/ILs composite films doped with 4%IL and annealed for 2 h reaches 0.64 V,which is twice to that of the control group of pure PLLA film.Therefore,by reasonably doping the PLLA films with IL and proper annealing treatment,it is possible to obtain piezoelectric thin films with high-voltage electrical properties of PLLA.