Substrate‐Versatile Direct‐Write Printing of Carbon Nanotube‐Based Flexible Conductors, Circuits, and Sensors
Year: 2021
Type: preprint
Abstract: Manufacturing of printed electronics relies on the deposition of conductive liquid inks, typically onto polymeric or paper substrates. Among available conductive fillers for use in electronic inks, carbon nanotubes (CNTs) have high conductivity, low density, processability at low temperatures, and intrinsic mechanical flexibility. However, the electrical conductivity of printed CNT structures has been limited by CNT quality and concentration, and by the need for nonconductive modifiers to make the ink stable and extrudable. This study introduces a polymer-free, printable aqueous CNT ink, and, via an ambient direct-write printing process, presents the relationships between printing resolution, ink rheology, and ink-substrate interactions. A model is constructed to predict printed feature sizes on impermeable substrates based on Wenzel wetting. Printed lines have conductivity up to 10 000 S m−1. The lines are flexible, with <5% change in DC resistance after 1000 bending cycles, and <3% change in DC resistance with a bending radius down to 1 mm. Demonstrations focus on i) conformality, via printing CNTs onto stickers that can be applied to curved surfaces, ii) interactivity using a CNT-based button printed onto folded paper structure, and iii) capacitive sensing of liquid wicking into the substrate itself. Facile integration of surface mount components on printed circuits is enabled by the intrinsic adhesion of the wet ink.
Institutions: Massachusetts Institute of Technology, Rice University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Awards: THE INSTITUTE FOR ULTRA-STRONG COMPOSITES BY COMPUTATIONAL DESIGN (US-COMP) WILL BE FOCUSED ON THE MODELING-DRIVEN DESIGN OF A NEW CLASS OF ULTRA-HIGH-STRENGTH-LIGHTWEIGHT (UHSL) MATERIALS FOR FUTURE MANNED MARS MISSIONS. THESE MATERIALS WILL MEET THE REQUIRED MECHANICAL PERFORMANCE GOALS SET FORTH BY NASA AND EXCEED THOSE EXHIBITED BY CURRENT STATE-OF-THE-ART CARBON-FIBER COMPOSITES. US-COMP S VISION IS TO SERVE AS A FOCAL POINT FOR PARTNERSHIPS BETWEEN NASA OTHER AGENCIES INDUSTRY AND ACADEMIA TO: (1) ENABLE COMPUTATIONALLY-DRIVEN DEVELOPMENT OF CARBON NANOTUBE (CNT)-BASED UHSL STRUCTURAL MATERIALS AND (2) EXPAND THE RESOURCE OF HIGHLY SKILLED ENGINEERS SCIENTISTS AND TECHNOLOGISTS IN THIS EMERGING FIELD TO ENHANCE THE U.S. LEADERSHIP IN CRITICAL LIGHTWEIGHT STRUCTURAL MATERIALS. THIS VISION WILL BE ACHIEVED THROUGH THE FOUR PRINCIPLE OBJECTIVES: ESTABLISH A NEW COMPUTATIONALLY-DRIVEN MATERIAL DESIGN PARADIGM FOR RAPID MATERIAL DEVELOPMENT AND DEPLOYMENT DEVELOP A NOVEL UHSL STRUCTURAL MATERIAL FOR USE IN DEEP SPACE EXPLORATION. THE PANEL-LEVEL TESTS AND DEMONSTRATION OF THE NOVEL MATERIALS WILL BE CARRIED OUT TO MOVE THE DEVELOPED TECHNOLOGY TO A TECHNICAL READINESS LEVEL (TRL) OF 4. DEVELOP NOVEL MODELING PROCESSING AND TESTING TOOLS AND METHODS FOR CNT-BASED COMPOSITE MATERIALS ESTABLISH A POOL OF HIGHLY SKILLED ENGINEERS AND SCIENTISTS TO CONTRIBUTE TO THE MATERIALS DEVELOPMENT WORKFORCE. AN INTERDISCIPLINARY AND DIVERSE TEAM OF RESEARCHERS FROM ACADEMIA INDUSTRY AND NATIONAL LABS WILL PARTICIPATE IN THE PROJECT. THE COMPUTATIONAL DESIGN OF THE MATERIAL WILL BE DRIVEN BY A MODELING EFFORT TO INTEGRATE TOPOLOGICAL OPTIMIZATION ATOMISTIC MODELING MOLECULAR MODELING MESOSCALE MODELING AND CONTINUUM-BASED COMPUTATIONAL MECHANICS. INNOVATIONS IN MATERIALS SYNTHESIS AND MANUFACTURING TECHNIQUES WILL ENSURE THE PERFORMANCE AND SCALE-UP FABRICATION OF AEROSPACE-QUALITY TEST SAMPLES AND PANELS. MULTISCALE TESTING AND CHARACTERIZATION CAPABILITIES WILL BE ESTABLISHED AND INTEGRATED TO VALIDATE THE MODELING AND MANUFACTURING EFFORTS AND TO COMPLETE THE PROOF-OF-CONCEPT CYCLE. PARTICIPATION OF THE INDUSTRIAL PARTNERS WILL PROVIDE AND ENSURE THE SCALABILITY AND AEROSPACE-GRADE QUALITY OF THE DEVELOPED COMPOSITE MATERIAL. THE DEVELOPED MATERIALS AND MATERIALS DEVELOPMENT METHODS WILL HAVE A MAJOR IMPACT ON THE AEROSPACE COMMUNITY. FIRST UHSL MATERIALS WILL BE DEVELOPED WITH THE RIGOROUS STRENGTH MODULUS AND FRACTURE TOUGHNESS PROPERTIES NECESSARY FOR MANNED MARS MISSIONS. SECOND A NEW COMPUTATIONALLY-DRIVEN MATERIALS DESIGN PARADIGM WILL BE ESTABLISHED TO DEVELOP THE UHSL MATERIAL OF INTEREST AND FOR FUTURE RAPID MATERIALS DESIGN AND DEVELOPMENT EFFORTS. THIRD A FUNDAMENTAL UNDERSTANDING OF LOAD TRANSFER AND MULTISCALE FAILURE MECHANISMS OF CNT-BASED COMPOSITE MATERIALS WILL BE ESTABLISHED TO ACHIEVE THEIR THEORETICAL PERFORMANCE. FOURTH A REPRODUCIBLE ENGINEERING PERFORMANCE DATA FROM AEROSPACE-QUALITY AND SCALE-UP PANEL TEST RESULTS BUILDING UPON AEROSPACE-GRADE RESIN SYSTEMS AND HIGH-QUALITY COMMERCIALLY AVAILABLE CNT MATERIALS TO ENSURE SCALABILITY TO CONDUCT ASTM STANDARD TESTS. ANOTHER IMPORTANT EMPHASIS OF THE INSTITUTE WILL BE IN WORKFORCE DEVELOPMENT. STUDENTS WILL BE TRAINED FOR DEVELOPING AND UTILIZING ADVANCED COMPUTATIONAL AND EXPERIMENTAL APPROACHES FOR LIGHTWEIGHT MATERIALS. FUNDS WILL BE RESERVED FOR THE STUDENTS TO HAVE EXTENDED VISITS TO NASA FACILITIES DURING SUMMER MONTHS FOR DIRECT MENTORSHIP BY NASA RESEARCHERS. THESE ACTIVITIES WILL STRENGTHEN THE PARTNERSHIPS BETWEEN THE INSTITUTE MEMBERS AND NASA. WITH THE HELP OF THE HBCU PARTICIPANT (FLORIDA A&M UNIVERSITY) THE INSTITUTE WILL ESTABLISH A DIVERSE GROUP OF BOTH RESEARCHERS AND GRADUATE STUDENTS., SIGNIFICANT LIMITATIONS TO SPACE EXPLORATION AND VEHICLE PERFORMANCE ARISE DUE TO THE USE OF OVER-ENGINEERED AND INEFFICIENT MATERIALS. SPECIFICALLY,, MIT Materials Research Science and Engineering Center - Full Proposal
OpenAlex ID: W3164210364