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Deformable liquid metal polymer composites with tunable electronic and mechanical properties

  • Amanda Koh (a1), Jennifer Sietins (a2), Geoffrey Slipher (a1) and Randy Mrozek (a3)

Room-temperature liquid metals, such as eutectic gallium–indium–tin (galinstan), dispersed in a polymer matrix present unique potential as conductors that may have minimal influence on the host polymer mechanical performance while providing enhanced electrical performance. Work described herein systematically evaluates the influence of uncured polydimethylsiloxane (PDMS) viscosity and galinstan loading on final dispersion viscosity and cured modulus. Dispersions of up to 80 vol% galinstan were obtained with relative permittivity values up to 170 that otherwise exhibited similar uncured rheological changes to a solid filler. Cured galinstan-in-PDMS dispersions, however, exhibited a reduced stiffness increase with respect to the host polymer relative to a solid filler. At a critical PDMS viscosity and metal, loading phase inversion to a conductive PDMS-in-metal dispersion was observed. It is anticipated that this work will enable the development of liquid metal polymer composites with independently controlled mechanical and electrical properties for a wide variety of stretchable electronic applications.

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1.Zare, Y. and Shabani, I.: Polymer/metal nanocomposites for biomedical applications. Mater. Sci. Eng., C 60, 195 (2016).
2.Kim, S-R., Kim, J-H., and Park, J-W.: Wearable and transparent capacitive strain sensor with high sensitivity based on patterned Ag nanowire networks. ACS Appl. Mater. Interfaces 9, 26407 (2017).
3.Lazarus, N., Meyer, C.D., Bedair, S.S., Slipher, G.A., and Kierzewski, I.M.: Magnetic elastomers for stretchable inductors. ACS Appl. Mater. Interfaces 7, 10080 (2015).
4.Park, M., Park, J., and Jeong, U.: Design of conductive composite elastomers for stretchable electronics. Nano Today 9, 244 (2014).
5.Mrozek, R.A., Cole, P.J., Mondy, L.A., Rao, R.R., Bieg, L.F., and Lenhart, J.L.: Highly conductive, melt processable polymer composites based on nickel and low melting eutectic metal. Polymer 51, 2954 (2010).
6.Stoyanov, H., Kollosche, M., Risse, S., Waché, R., and Kofod, G.: Soft conductive elastomer materials for stretchable electronics and voltage controlled artificial muscles. Adv. Mater. 25, 578 (2013).
7.Al-Saleh, M.H. and Sundararaj, U.: Electromagnetic interference shielding mechanisms of CNT/polymer composites. Carbon 47, 1738 (2009).
8.Voet, A.: Dielectrics and rheology of non-aqueous dispersions. J. Phys. Colloid Chem. 51, 1037 (1947).
9.Pal, R.: Effect of droplet size on the rheology of emulsions. AIChE J. 42, 3181 (1996).
10.Seth, J.R., Mohan, L., Locatelli-Champagne, C., Cloitre, M., and Bonnecaze, R.T.: A micromechanical model to predict the flow of soft particle glasses. Nat. Mater. 10, 838 (2011).
11.Pishvaei, M., Graillat, C., McKenna, T.F., and Cassagnau, P.: Rheological behaviour of polystyrene latex near the maximum packing fraction of particles. Polymer 46, 1235 (2005).
12.Olhero, S.M. and Ferreira, J.M.F.: Influence of particle size distribution on rheology and particle packing of silica-based suspensions. Powder Technol. 139, 69 (2004).
13.Itabashi, Y., Inoue, M., and Tada, Y.: Effect of filler morphology on fatigue properties of stretchable wires printed with Ag pastes. In International Conference on Electronics Packaging (ICEP) (IEEE, Piscataway, NJ, 2014); p. 752.
14.Kim, K.S., Zhao, Y., Jang, H., Lee, S.Y., Kim, J.M., Kim, K.S., Ahn, J-H., Kim, P., Choi, J-Y., and Hong, B.H.: Large-scale pattern growth of graphene films for stretchable transparent electrodes. Nature 457, 706 (2009).
15.Liu, H., Li, Y., Dai, K., Zheng, G., Liu, C., Shen, C., Yan, X., Guo, J., and Guo, Z.: Electrically conductive thermoplastic elastomer nanocomposites at ultralow graphene loading levels for strain sensor applications. J. Mater. Chem. C 4, 157 (2016).
16.Sekitani, T., Nakajima, H., Maeda, H., Fukushima, T., Aida, T., Hata, K., and Someya, T.: Stretchable active-matrix organic light-emitting diode display using printable elastic conductors. Nat. Mater. 8, 494 (2009).
17.Bartlett, M.D., Fassler, A., Kazem, N., Markvicka, E.J., Mandal, P., and Majidi, C.: Stretchable, high-k dielectric elastomers through liquid-metal inclusions. Adv. Mater. 28, 3726 (2016).
18.Dickey, M.D.: Stretchable and soft electronics using liquid metals. Adv. Mater. 29, 1606425 (2017).
19.Kazem, N., Hellebrekers, T., and Majidi, C.: Soft multifunctional composites and emulsions with liquid metals. Adv. Mater. 29, 1605985 (2017).
20.Tabatabai, A., Fassler, A., Usiak, C., and Majidi, C.: Liquid-phase gallium–indium alloy electronics with microcontact printing. Langmuir 29, 6194 (2013).
21.Khan, M.R., Trlica, C., So, J-H., Valeri, M., and Dickey, M.D.: Influence of water on the interfacial behavior of gallium liquid metal alloys. ACS Appl. Mater. Interfaces 6, 22467 (2014).
22.Khoshmanesh, K., Tang, S-Y., Zhu, J.Y., Schaefer, S., Mitchell, A., Kalantar-zadeh, K., and Dickey, M.D.: Liquid metal enabled microfluidics. Lab Chip 17, 974 (2017).
23.Ladd, C., So, J-H., Muth, J., and Dickey, M.D.: 3D printing of free standing liquid metal microstructures. Adv. Mater. 25, 5081 (2013).
24.Parekh, D.P., Ladd, C., Panich, L., Moussa, K., and Dickey, M.D.: 3D printing of liquid metals as fugitive inks for fabrication of 3D microfluidic channels. Lab Chip 16, 1812 (2016). Gans, B-J., Duineveld, P.C., and Schubert, U.S.: Inkjet printing of polymers: State of the art and future developments. Adv. Mater. 16, 203 (2004).
26.Teng, W.D., Edirisinghe, M.J., and Evans, J.R.G.: Optimization of dispersion and viscosity of a ceramic jet printing ink. J. Am. Ceram. Soc. 80, 486 (1997).
27.Koh, A., Mrozek, R., and Slipher, G.: Characterization and manipulation of interfacial activity for aqueous galinstan dispersions. Adv. Mater. Interfaces 5, 1701240 (2018).
28.Xu, Q., Oudalov, N., Guo, Q., Jaeger, H.M., and Brown, E.: Effect of oxidation on the mechanical properties of liquid gallium and eutectic gallium–indium. Phys. Fluids 24, 063101 (2012).
29.Gutiérrez, J.M., González, C., Maestro, A., Solè, I., Pey, C.M., and Nolla, J.: Nano-emulsions: New applications and optimization of their preparation. Curr. Opin. Colloid Interface Sci. 13, 245 (2008).
30.Singh, Y., Meher, J.G., Raval, K., Khan, F.A., Chaurasia, M., Jain, N.K., and Chourasia, M.K.: Nanoemulsion: Concepts, development and applications in drug delivery. J. Controlled Release 252, 28 (2017).
31.Mrozek, R.A., Knorr, D.B., Spangler, S.W., Cole, P.J., and Lenhart, J.L.: Impact of precursor size on the chain structure and mechanical properties of solvent-swollen epoxy gels. Soft Matter 8, 11185 (2012).
32.Song, C., Wang, P., and Makse, H.A.: A phase diagram for jammed matter. Nature 453, 629 (2008).
33.Masalova, I., Foudazi, R., and Malkin, A.Y.: The rheology of highly concentrated emulsions stabilized with different surfactants. Colloids Surf., A 375, 76 (2011).
34.Pal, R.: Yield stress and viscoelastic properties of high internal phase ratio emulsions. Colloid Polym. Sci. 277, 583 (1999).
35.Thelen, J., Dickey, M.D., and Ward, T.: A study of the production and reversible stability of EGaIn liquid metal microspheres using flow focusing. Lab Chip 12, 3961 (2012).
36.Hutter, T., Bauer, W-A.C., Elliott, S.R., and Huck, W.T.S.: Formation of spherical and non-spherical eutectic gallium–indium liquid–metal microdroplets in microfluidic channels at room temperature. Adv. Funct. Mater. 22, 2624 (2012).
37.Hohman, J.N., Kim, M., Wadsworth, G.A., Bednar, H.R., Jiang, J., LeThai, M.A., and Weiss, P.S.: Directing substrate morphology via self-assembly: Ligand-mediated scission of gallium–indium microspheres to the nanoscale. Nano Lett. 11, 5104 (2011).
38.Lin, Y., Liu, Y., Genzer, J., and Dickey, M.D.: Shape-transformable liquid metal nanoparticles in aqueous solution. Chem. Sci. 8, 3832 (2017).
39.Jeong, S.H., Chen, S., Huo, J., Gamstedt, E.K., Liu, J., Zhang, S-L., Zhang, Z-B., Hjort, K., and Wu, Z.: Mechanically stretchable and electrically insulating thermal elastomer composite by liquid alloy droplet embedment. Nature 5, 18257 (2015).
40.Fan, P., Sun, Z., Wang, Y., Chang, H., Zhang, P., Yao, S., Lu, C., Rao, W., and Liu, J.: Nano liquid metal for the preparation of a thermally conductive and electrically insulating material with high stability. RSC Adv. 8, 16232 (2018).
41.Luckham, P.F. and Ukeje, M.A.: Effect of particle size distribution on the rheology of dispersed systems. J. Colloid and Interface Sci. 220, 347 (1999).
42.Sharu, B.K., Simon, G.P., Cheng, W., Zank, J., and Bhattacharyya, A.R.: Development of microstructure and evolution of rheological characteristics of a highly concentrated emulsion during emulsification. Colloids Surf., A 532, 342 (2017).
43.Masalova, I. and Malkin, A.Y.: Peculiarities of rheological properties and flow of highly concentrated emulsions: The role of concentration and droplet size. Colloid J. 69, 185 (2007).
44.Huang, S.H., Liu, P., Mokasdar, A., and Hou, L.: Additive manufacturing and its societal impact: A literature review. Int. J. Adv. Manuf. Technol. 67, 1191 (2013).
45.Wang, X., Jiang, M., Zhou, Z., Gou, J., and Hui, D.: 3D printing of polymer matrix composites: A review and prospective. Composites, Part B 110, 442 (2017).
46.Mewis, J. and Spaull, A.J.B.: Rheology of concentrated dispersions. Adv. Colloid Interface Sci. 6, 173 (1976).
47.Guth, E.: Theory of filler reinforcement. J. Appl. Phys. 16, 20 (1945).
48.Fu, S-Y., Feng, X-Q., Lauke, B., and Mai, Y-W.: Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate–polymer composites. Composites, Part B 39, 933 (2008).
49.Style, R.W., Boltyanskiy, R., Allen, B., Jensen, K.E., Foote, H.P., Wettlaufer, S.J., and Dufresne, E.R.: Stiffening solids with liquid inclusions. Nat. Phys. 11, 82 (2014).
50.Dang, Z-M., Yuan, J-K., Zha, J-W., Zhou, T., Li, S-T., and Hu, G-H.: Fundamentals, processes and applications of high-permittivity polymer–matrix composites. Prog. Mater. Sci. 57, 660 (2012).
51.Liu, X., Katehi, L.P.B., and Peroulis, D.: Non-toxic liquid metal microstrip resonators 2009. In Asia Pacific Microwave Conference (IEEE, Piscataway, NJ, 2009); p. 131.
52.John, R.: High dielectric constant gate oxides for metal oxide Si transistors. Rep. Prog. Phys. 69, 327 (2006).
53.Farrell, T. and Greig, D.: The electrical resistivity of nickel and its alloys. J. Phys. C: Solid State Phys. 1, 1359 (1968).
54.Qian, C. and McClements, D.J.: Formation of nanoemulsions stabilized by model food-grade emulsifiers using high-pressure homogenization. Factors affecting particle size. Food Hydrocolloids 25, 1000 (2011).
55.Abismaïl, B., Canselier, J.P., Wilhelm, A.M., Delmas, H., and Gourdon, C.: Emulsification by ultrasound: Drop size distribution and stability. Ultrason. Sonochem. 6, 75 (1999).
56.Floury, J., Desrumaux, A., and Lardières, J.: Effect of high-pressure homogenization on droplet size distributions and rheological properties of model oil-in-water emulsions. Innovative Food Sci. Emerging Technol. 1, 127 (2000).
57.Fernandez, P., André, V., Rieger, J., and Kühnle, A.: Nano-emulsion formation by emulsion phase inversion. Colloids Surf., A 251, 53 (2004).
58.Daalkhaijav, U., Yirmibesoglu, O.D., Walker, S., and Mengüç, Y.: Rheological modification of liquid metal for additive manufacturing of stretchable electronics. Adv. Mater. Technol. 3, 1700351 (2018).
59.Steinmann, S., Gronski, W., and Friedrich, C.: Quantitative rheological evaluation of phase inversion in two-phase polymer blends with cocontinuous morphology. Rheol. Acta 41, 77 (2002).
60.Steinmann, S., Gronski, W., and Friedrich, C.: Influence of selective filling on rheological properties and phase inversion of two-phase polymer blends. Polymer 43, 4467 (2002).
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