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Abstract Plants produce a wide range of bioactive phytochemicals, such as antioxidants and vitamins, which play crucial roles in aging prevention, inflammation reduction, and reducing the risk of cancer. Selectively harvesting these phytochemicals, such as lycopene, from tomatoes through the adsorption method is cost‐effective and energy efficient. In this work, a templated synthesis of 3D‐printed crosslinked cyclodextrin polymers featuring nanotubular structures for highly selective lycopene harvesting is reported. Polypseudorotaxanes formed by triethoxysilane‐based telechelic polyethylene glycols and α‐cyclodextrins (α‐CDs) are designed as the template to (1) synthetically access urethane‐based nanotubular structures at the molecular level, and (2) construct 3D‐printed architectures with designed macroscale voids. The polypseudorotaxane hydrogels showed good rheological properties for direct ink writing, and the 3D‐printed hydrogels were converted to the desired α‐CD polymer network through a three‐step postprinting transformation. The obtained urethane‐crosslinked α‐CD monoliths possess nanotubular structures and 3D‐printed voids. They selectively adsorb lycopene from raw tomato juice, protecting lycopene from photo‐ or thermo‐degradations. This work highlights the hierarchically templated synthesis approach in developing functional 3D‐printing materials by connecting the bottom‐up molecular assembly and synthesis with the top‐down 3D architecture control and fabrication.
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Thermo-responsive 3D-printed polyrotaxane monolith
Thermo-responsive 3D-printed hydrogels that are composed of methylated α-cyclodextrin polyrotaxanes have been synthesized through post-3D-printing methylation. With a high methylation degree of the threaded α-cyclodextrins, the fabricated monolith exhibits a two-stage thermo-induced aggregation behavior, in which a second micro-crystallization process was identified for the first time. The methylated polyrotaxane monoliths possess reversible temperature-dependent size, transparency, and elastic moduli switching in an aqueous environment. Through dual-material 3D printing, the 3D-printed monolith actuates back-and-forth at different temperatures.
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- Award ID(s):
- 1757371
- PAR ID:
- 10125294
- Date Published:
- Journal Name:
- Polymer Chemistry
- ISSN:
- 1759-9954
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Additive manufacturing (AM), also known as 3D printing, has significantly advanced in recent years, especially with the introduction of multifunctional 3D-printed parts. AM fabricated monolith has multiple material capabilities, thus various functionalities are well-perceived by the manufacturing communities. As an example, a traditional fused filament fabrication (FFF) 3D printer fabricates multi-material thermoplastic parts using a dual extrusion system to increase the functionality of the part including variable stiffening and gradient structures. In addition to the multiple thermoplastic feedstocks in a dual extrusion system, multifunctional AM can be achieved by embedding electronics or reinforcing fibers within the fabricated thermoplastic parts, which significantly impacts the rapid prototyping of hybrid components in manufacturing industries. State-of-the-art techniques such as coextrusion systems, ultrasonic welding tools, and thermal embedding tools have been implemented to automate the process of embedding conductive material within the 3D-printed thermoplastic substrate. The goal of this tool development effort is to embed wires within 3D 3D-printed plastic substrate. This research consisted of developing a wire embedding tool that can be integrated into an FFF desktop 3D printer to deposit conductive as well as resistive wires within the 3D-printed thermoplastic substrate. By realizing the challenges for discrete materials interaction at the interface such as nichrome wires and Acrylonitrile Butadiene Styrene (ABS) plastics and polylactic acid (PLA), the goal of this tool was to immerse wire within ABS and PLA substrate using transient swelling mechanisms under non-polar solvent. A proof-of-concept test stands with a wire feed system and the embedding wheel was first designed and manufactured using 3D printing to examine if a traditional roller-guided system, primarily used for plastic extrusion, would be sufficient for wire extrusion. The development of the integrated wire embedding tool was initiated based on the success of the proof-of-concept wire extrusion system. The design of the integrated wire embedding tool consisted of three sub-assemblies: wire delivery assembly, wire shearing assembly, and swivel assembly. The wire delivery assembly is responsible for feeding the wire towards the thermoplastic using the filament delivery system seen within FFF printers. For the wire shearing mechanism, a cutting Tungsten carbide blade in conjunction with a Nema-17 external stepper motor was used to shear the wire. For the wire embedding assembly, a custom swivel mount was fabricated with a bearing housing for a ball bearing that allowed for a 360-degree motion around the horizontal plane. A wire guide nozzle was placed through the mount to allow for the wire to be fed down into a brass embedding wheel in a tangential manner. Additionally, the solvent reservoir was mounted such that an even layer of solution was dispensed onto the thermoplastic substrate. Through this tool development effort, the aim was to develop technologies that will enable 3D printing of wire-embedded monolith for various applications including a self-heating mold of thermoset-based composite manufacturing as well as smart composites with embedded sensors.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9PY01510H
