Abstract
Ultraviolet (UV) printing of photopolymers is a widely adopted manufacturing method because of its high resolution and throughput. However, available printable photopolymers are typically thermosets, resulting in challenges in postprocessing and recycling of printed structures. Here, we present a new process called interfacial photopolymerization (IPP) which enables photopolymerization printing of linear chain polymers. In IPP, a polymer film is formed at the interface between two immiscible liquids, one containing a chain-growth monomer and the other containing a photoinitiator. We demonstrate the integration of IPP in a proof-of-concept projection system for printing of polyacrylonitrile (PAN) films and rudimentary multi-layer shapes . IPP shows in-plane and out-of-plane resolutions comparable to conventional photoprinting methods. Cohesive PAN films with number-average molecular weights greater than 15 kg mol-1 are obtained, and to our knowledge this is the first report of photopolymerization printing of PAN. A macrokinetics model of IPP is developed to elucidate the transport and reaction rates involved and evaluate how reaction parameters affect film thickness and print speed. Last, demonstration of IPP in a multilayer scheme suggests its suitabiliy for three-dimensional printing of linear-chain polymers.
Original language | English (US) |
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Pages (from-to) | 31009-31019 |
Number of pages | 11 |
Journal | ACS Applied Materials and Interfaces |
Volume | 15 |
Issue number | 25 |
DOIs | |
State | Published - Jun 28 2023 |
Funding
Financial support was provided by the National Science Foundation (CMMI-2114343) and by a gift from the Ryder Charitable Foundation. C.A.C. was partially supported by a MathWorks Engineering Fellowship at MIT for academic years 2020-2021 and 2021-2022. The authors thank Prajwal Tumkur Mahesh, Jada Jackman, and Alison Grafton for their support in conducting multilayer printing experiments and verifying repeatability of the IPP process; Ryan Oliver, Benjamin Miller and Prof. Mathias Kolle for their input in the design and assembly of the projection optical train; Daniel Gilbert, Paul Carson, and Joseph D. Sandt for help with design and manufacturing of custom mechanical parts for the printing setup; Carl Thrasher for support with gel permeation chromatography measurements and valuable feedback on the manuscript; and Prof. Zachary P. Smith and Dr. Justin Teesdale for access to thermogravimetric analysis tools and associated support. This work made use of the electron microscopy facilities at MIT.nano, and nuclear magnetic resonance instruments in the Department of Chemistry Instrumentation Facility (DCIF) at MIT.
Keywords
- DLP printing
- interfacial polymerization
- macrokinetics
- polymer
- thermoplastic
ASJC Scopus subject areas
- General Materials Science