Solution-Processed, Photo-Patternable Fluorinated Sol-Gel Hybrid Materials as a Bio-Fluidic Barrier for Flexible Electronic Systems
United States | Advanced Electronic Materials
2020-01-15 | 바로가기
Flexible, Hybrid_Materials, sol_gel_processing
Cited by 1
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Advanced Electronic Materials
First published: 15 January 2020
Injun Lee1, Yong Ho Kim1,2, Jinhyeong Jang2, Kwang-Heum Lee1,2, Junho Jang1,2, Young-Woo Lim1,2, Sang-Hee Ko Park1,2, Chan Beum Park2, Wonryung Lee1,2, and Byeong-Soo Bae1
1 Wearable Platform Materials Technology Center, Korea Advanced Institute of Science and Technology
2 Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology
Reports have recently been published on ultrathin biofluid barriers, which enable the long‐term measurement of biological signals and exhibit conformability on nonlinear surfaces such as skin and organs. However, inorganic‐ and organic‐based barriers have process incompatibility and high water permeability, respectively. Siloxane‐ (inorganic) based fluorinated epoxy (organic) hybrid materials (FEH) are demonstrated for bio‐fluidic barrier and the biocompatibility and barrier performance for flexible electronic systems as solution‐processed oxide thin‐film transistors (TFTs) on 1.2 µm thick polyimide (PI) thin film substrate is confirmed. FEH thin film can be patterned as small as 10 µm through conventional photolithography. The fabricated solution‐processed indium oxide TFTs with FEH barriers exhibit durable performance over 16 h with no dramatic change of transfer characteristics in phosphate‐buffered saline (PBS) environment. Furthermore, to realize FEH barriers for flexible systems, the solution‐processed indium oxide TFTs with FEH barriers on ultrathin PI substrate are demonstrated subjected to compression test and successfully measure the electrical properties with no irreversible degradation during 1000 cycles of mechanical testing in PBS.
In this work, we demonstrate a sol‐gel derived fluorinated epoxy hybrimer for use as a bio‐fluidic barrier in solution processes. Photo‐patternable FEH can be micro‐patterned, with features as small as 10 µm. Due to the fluorine functional group, FEH has superior water resistivity and hydrophobicity compared to other organic films, which is verified by magnesium soaking test and water contact angle measurement. Also, we confirmed that FEH is a biocompatible material through in vitro biocompatibility test using rat cardiomyocytes. To demonstrate FEH as a bio‐fluidic barrier, we fabricated solution oxide TFTs with FEH barrier layer and measured the transfer characteristics of oxide TFTs in the PBS environment. The oxide TFTs with FEH barrier exhibit durable performance during 16 h, with no dramatic change of electrical properties in PBS environment. To evaluate the electrical stability of the barrier in a bio‐fluidic environment, we use EIS analysis to confirm that FEH films exhibit no resistive leakage through defects and that they have high signal stability. Furthermore, indium oxide TFTs with FEH barriers on ultra‐thin PI substrates demonstrate no degradation of electrical properties, even during 1000 repeated cycles of 30% compression and re‐stretch under PBS droplet. We envision that our sol‐gel processed FEH films will be utilized as bio‐fluidic barriers for flexible and conformable electronics.
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