Radu Elena Ruxandra, Panaitescu Denis Mihaela, Andrei Laura, Ciuprina Florin, Nicolae Cristian Andi, Gabor Augusta Raluca, Truşcă Roxana
National Institute for R&D in Chemistry and Petrochemistry ICECHIM, 202 Spl. Indendentei, 060021 Bucharest, Romania.
ELMAT Laboratory, Faculty of Electrical Engineering, University Politehnica of Bucharest, 313 Spl. Indendentei, 060042 Bucharest, Romania.
Nanomaterials (Basel). 2021 Dec 29;12(1):95. doi: 10.3390/nano12010095.
Polymer nanodielectrics characterized by good flexibility, processability, low dielectric loss and high dielectric permittivity are materials of interest for wearable electronic devices and intelligent textiles, and are highly in demand in robotics. In this study, an easily scalable and environmentally friendly method was applied to obtain polysiloxane/nanosilica nanocomposites with a large content of nanofiller, of up to 30% by weight. Nanosilica was dispersed both as individual particles and as agglomerates; in nanocomposites with a lower amount of filler, the former prevailed, and at over 20 wt% nanosilica the agglomerates predominated. An improvement of both the tensile strength and modulus was observed for nanocomposites with 5-15 wt% nanosilica, and a strong increase of the storage modulus was observed with the increase of nanofiller concentration. Furthermore, an increase of the storage modulus of up to seven times was observed in the nanocomposites with 30 wt% nanosilica. The tensile modulus was well fitted by models that consider the aggregation of nanoparticles and the role of the interface. The dielectric spectra showed an increase of the real part of the complex relative permittivity with 33% for 30 wt% nanosilica in nanocomposites at a frequency of 1 KHz, whereas the loss tangent values were lower than 0.02 for all tested nanodielectrics in the radio frequency range between 1 KHz and 1 MHz. The polysiloxane-nanosilica nanocomposites developed in this work showed good flexibility; however, they also showed increased stiffness along with a stronger dielectric response than the unfilled polysiloxane, which recommends them as dielectric substrates for wearable electronic devices.
具有良好柔韧性、可加工性、低介电损耗和高介电常数的聚合物纳米电介质是可穿戴电子设备和智能纺织品所关注的材料，在机器人技术中也有很高的需求。在本研究中，采用了一种易于扩展且环保的方法来制备具有高达30重量%的高含量纳米填料的聚硅氧烷/纳米二氧化硅纳米复合材料。纳米二氧化硅既以单个颗粒形式分散，也以团聚体形式存在；在填料含量较低的纳米复合材料中，前者占主导，而当纳米二氧化硅含量超过20重量%时，团聚体占主导。对于含有5-15重量%纳米二氧化硅的纳米复合材料，观察到拉伸强度和模量均有所提高，并且随着纳米填料浓度的增加，储能模量显著增加。此外，在含有30重量%纳米二氧化硅的纳米复合材料中，观察到储能模量增加了高达七倍。拉伸模量通过考虑纳米颗粒聚集和界面作用的模型得到了很好的拟合。介电谱显示，在1 kHz频率下，含有30重量%纳米二氧化硅的纳米复合材料的复相对介电常数实部增加了33%，而在1 kHz至1 MHz的射频范围内，所有测试的纳米电介质的损耗角正切值均低于0.02。本工作中开发的聚硅氧烷-纳米二氧化硅纳米复合材料显示出良好的柔韧性；然而，它们也表现出硬度增加，并且比未填充的聚硅氧烷具有更强的介电响应，这使其成为可穿戴电子设备的介电基板。
