氟橡膠/銀銅粉/離子液體可拉伸導電彈性體的電性與機械性質分析

Electrical and Mechanical Properties of the Stretchable Conductive Elastomers Formed by Fluorine Rubber/Silver-Coated Copper/Ionic Liquid

黃譯鋐(I-Hung Huang)

指導教授 ： 童世煌

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202002211

摘要

本研究利用氟橡膠、銀銅粉及離子液體製備拉伸導電彈性體。透過分析三者間的交互作用，了解不同條件對導電彈性體的影響，並利用交聯氟橡膠的方式，提升導電彈性體的回復性。我們分別探討銀銅粉的尺寸和形狀、導電膠溶液的黏度、交聯方式和添加與氟橡膠相容及部分相容的離子液體對拉伸及導電的影響。從實驗結果發現，拉伸性隨著尺寸提升而急遽下降；而為了增加彈性體的拉伸性及導電性，需要調配適當黏度的導電膠，以利成膜後金屬達到較好的分散於彈性體中；透過將氟橡膠在溶液中先進行交聯反應，再進行熱交聯，可進一步提高彈性體的拉伸性和回復性；將離子液體加入交聯導電彈性體中，可有效塑化交聯氟橡膠，改善隨拉伸變化的導電度，尤其是添加和氟橡膠相容的離子液體，拉伸性及導電性效果最佳。透過應力鬆弛(stress relaxation)實驗發現導電彈性體模數隨時間的變化是影響導電度變化的關鍵。在導電彈性體中添加和氟橡膠相容的離子液體，斷裂伸長率可提升到340%的應變，而且在50%固定應變下的回復性測試中，可以維持在1000Ω以下的電阻值，並在彎曲及摺疊測試中也都能保持良好的導電性。本研究開發的導電彈性體對於應用在穿戴式裝置上具有很大的潛力。

關鍵字

拉伸導電彈性體 ； 氟橡膠 ； 離子液體 ； 銀銅粉 ； 交聯

並列摘要

In this work, we report a stretchable conductive elastomer containing fluorine rubber, silver-coated copper, and ionic liquids. The interplays among the three components were studied and the fluorine rubber was crosslinked to improve the elastic recoverability of the conductive elastomers. We investigated the effects of several factors on the tensile and electrical properties, including the size and shape of the silver-coated coppers, the viscosity of the pastes, the crosslinking method, and the compatibility of the ionic liquids with fluorine rubber. Our results show that the stretchability dramatically decreases with increasing size of the particles. To increase the properties of the elastomers, the viscosity of the paste needs to be controlled to achieve an appropriate distribution of the metal particles in the rubber during the drying process. The properties of the elastomers can be further improved through the pre-crosslinking of the fluorine rubber in solutions followed by thermal crosslinking. Moreover, the addition of ionic liquids can effectively plasticize the crosslinked fluorine rubber to improve the conductivity of the elastomers under stretching, especially the ionic liquids that are compatible with the fluorine rubber. Through the stress relaxation tests, we found that the change in the modulus of the elastomers with time caused by the ionic liquids is highly correlated with the conductivity change upon stretching. The optimized conductive elastomer shows an elongation break at 340% strain and a resistance lower than 1000 Ω in the stretch and release cycles at 50% strain. It also maintains a great conductivity in the bending and folding tests. The conductive elastomers developed in this work are potential for applications in wearable electronics.

並列關鍵字

stretchable conductive elastomer ； fluorine rubber ； ionic liquids ； silver-coated copper ； crosslinked

參考文獻

1. Wang, C.; Lee, W.-Y.; Kong, D.; Pfattner, R.; Schweicher, G.; Nakajima, R.; Lu, C.; Mei, J.; Lee, T. H.; Wu, H.-C.; Lopez, J.; Diao, Y.; Gu, X.; Himmelberger, S.; Niu, W.; Matthews, J. R.; He, M.; Salleo, A.; Nishi, Y.; Bao, Z., Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors. Scientific Reports 2015, 5 (1), 17849.

2. Sekitani, T.; Noguchi, Y.; Hata, K.; Fukushima, T.; Aida, T.; Someya, T., A Rubberlike Stretchable Active Matrix Using Elastic Conductors. Science 2008, 321 (5895), 1468.

3. Tee, B. C. K.; Wang, C.; Allen, R.; Bao, Z., An electrically and mechanically self-healing composite with pressure- and flexion-sensitive properties for electronic skin applications. Nature Nanotechnology 2012, 7 (12), 825-832.

4. Vural, M.; Behrens, A. M.; Ayyub, O. B.; Ayoub, J. J.; Kofinas, P., Sprayable Elastic Conductors Based on Block Copolymer Silver Nanoparticle Composites. ACS Nano 2015, 9 (1), 336-344.

5. Kastner, J.; Faury, T.; Außerhuber, H. M.; Obermüller, T.; Leichtfried, H.; Haslinger, M. J.; Liftinger, E.; Innerlohinger, J.; Gnatiuk, I.; Holzinger, D.; Lederer, T., Silver-based reactive ink for inkjet-printing of conductive lines on textiles. Microelectronic Engineering 2017, 176, 84-88.