(244g) Photothermal Effects of Plasmonic Nanoparticles to Enhance Diels–Alder (DA) Reactions in Reversible Thermosets
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Nanoscale Science and Engineering Forum
Nanomaterials for Energy Conversion
Wednesday, November 8, 2023 - 5:10pm to 5:30pm
Thermosets' excellent mechanical properties, chemical resistance, and thermal stability make them an
appealing material for additive manufacturing. Irreversible crosslinking and slow curing rate of
thermosets like epoxy, however, makes layer by layer printing difficult. We have developed a reversible
thermosets polymer incorporating thermo-reversible covalent adaptable network (Diels–Alder (DA)
reactions) into it and mixing that with refractory plasmonic titanium nitride (TiN) nanomaterials. TiN
nanoparticles can efficiently, rapidly convert broad spectrum visible light into localized heating to trigger
rapid polymerization and depolymerization reactions making them suitable for reprocessing as well as
additive manufacturing. Additionally, it provides opportunity for targeted repair of defect on a 3-D
printed epoxy structure and smoothing the rough surface of the finished products. In this study, a
comparative investigation was conducted between heat and light stimulus to examine their effect on
Diels-Alder reactions. Our in-situ FTIR study of reversible epoxy/TiN composites under light suggested
that broad spectrum white light can significantly enhance the reversible reactions. Interestingly, the
reaction rate with light is significantly faster than the reaction driven by heat even though the average
bulk temperature of the samples is similar. Plasmonic TiN nanostructures concentrate incident light in
nanometer-sized volumes to generate nanoscale heating which cause the local temperature around
nanoparticles hotter than the bulk temperature measured. Moreover, optical microscopy and atomic
force microscopy images demonstrate that we can use light to precisely depolymerize a selected surface
region of manufactured items to smooth out their rough surfaces or repair any cracks.
appealing material for additive manufacturing. Irreversible crosslinking and slow curing rate of
thermosets like epoxy, however, makes layer by layer printing difficult. We have developed a reversible
thermosets polymer incorporating thermo-reversible covalent adaptable network (Diels–Alder (DA)
reactions) into it and mixing that with refractory plasmonic titanium nitride (TiN) nanomaterials. TiN
nanoparticles can efficiently, rapidly convert broad spectrum visible light into localized heating to trigger
rapid polymerization and depolymerization reactions making them suitable for reprocessing as well as
additive manufacturing. Additionally, it provides opportunity for targeted repair of defect on a 3-D
printed epoxy structure and smoothing the rough surface of the finished products. In this study, a
comparative investigation was conducted between heat and light stimulus to examine their effect on
Diels-Alder reactions. Our in-situ FTIR study of reversible epoxy/TiN composites under light suggested
that broad spectrum white light can significantly enhance the reversible reactions. Interestingly, the
reaction rate with light is significantly faster than the reaction driven by heat even though the average
bulk temperature of the samples is similar. Plasmonic TiN nanostructures concentrate incident light in
nanometer-sized volumes to generate nanoscale heating which cause the local temperature around
nanoparticles hotter than the bulk temperature measured. Moreover, optical microscopy and atomic
force microscopy images demonstrate that we can use light to precisely depolymerize a selected surface
region of manufactured items to smooth out their rough surfaces or repair any cracks.