TY - JOUR
T1 - Transparent and Flexible Electronics Assembled with Metallic Nanowire-Layered Nondrying Glycerogel
AU - Seo, Yongbeom
AU - Kim, Byoung Soo
AU - Ballance, William C.
AU - Aw, Natalie
AU - Sutton, Brad
AU - Kong, Hyunjoon
N1 - We acknowledge the financial support from the National Institutes of Health (Grant 1R01 HL109192 and 1R21 HL131469 to H.K.), National Science Foundation (STC-EBICS Grant CBET-0939511 to H.K.), Korea Institute of Industrial Technology (JEI40004), and TechnipFMC (IL Reference #093250 to W.C.B.). Y.S. thanks J. Soh for the graphic assists and scientific discussions. W.C.B. thanks Y. Deng for video editing assistance. Raman and TGA were performed at the Frederick Seitz Materials Research Laboratory Central Facilities at the University of Illinois. MRI was performed at the Biomedical Imaging Center of the Beckman Institute for Advanced Science and Technology at the University of Illinois (UIUC-BI-BIC).
PY - 2020/3/18
Y1 - 2020/3/18
N2 - There has been increasing demand for transparent and mechanically durable electrical conductors for their uses in wearable electronic devices. It is common to layer metallic nanowires on transparent but stiff poly(dimethylsiloxane) (PDMS) or stretchable but opaque Ecoflex-based substrates. Here, we hypothesized that layering metallic nanowires on a stretchable and hygroscopic gel would allow us to assemble a transparent, stretchable, and durable conductor. The hygroscopic property of the gel was attained by partially replacing water in the preformed polyacrylamide hydrogel with glycerol. The resulting gel, denoted as a glycerogel, could remain hydrated for over 6 months in air by taking up water molecules from the air. The glycerogel was tailored to be stretchable up to 8 times its original length by tuning the amount of the cross-linker and acrylamide. The resulting glycerogel allowed for deposition of wavy silver nanowires using the prestrain method up to 400% prestrain, without causing kinks and interfacial cracks often found with nanowires layered onto PDMS. With a prestrain of 100%, the resulting nanowire-gel conductor exhibited optical transparency (85%) and electrical conductivity (17.1 ohm/sq) even after 5000 cycles of deformation. The results of this study would broadly be useful to improve the performance of the next generation of flexible electronic devices.
AB - There has been increasing demand for transparent and mechanically durable electrical conductors for their uses in wearable electronic devices. It is common to layer metallic nanowires on transparent but stiff poly(dimethylsiloxane) (PDMS) or stretchable but opaque Ecoflex-based substrates. Here, we hypothesized that layering metallic nanowires on a stretchable and hygroscopic gel would allow us to assemble a transparent, stretchable, and durable conductor. The hygroscopic property of the gel was attained by partially replacing water in the preformed polyacrylamide hydrogel with glycerol. The resulting gel, denoted as a glycerogel, could remain hydrated for over 6 months in air by taking up water molecules from the air. The glycerogel was tailored to be stretchable up to 8 times its original length by tuning the amount of the cross-linker and acrylamide. The resulting glycerogel allowed for deposition of wavy silver nanowires using the prestrain method up to 400% prestrain, without causing kinks and interfacial cracks often found with nanowires layered onto PDMS. With a prestrain of 100%, the resulting nanowire-gel conductor exhibited optical transparency (85%) and electrical conductivity (17.1 ohm/sq) even after 5000 cycles of deformation. The results of this study would broadly be useful to improve the performance of the next generation of flexible electronic devices.
KW - flexible electronics
KW - glycerol
KW - hydration
KW - stretchable hydrogel
KW - toughness
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U2 - 10.1021/acsami.9b21697
DO - 10.1021/acsami.9b21697
M3 - Article
C2 - 32072806
AN - SCOPUS:85082098795
SN - 1944-8244
VL - 12
SP - 13040
EP - 13050
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 11
ER -