A5041802438- Photopolymerization techniques and applications
- Additive Manufacturing and 3D Printing Technologies
- biodegradable polymer synthesis and properties
- Polymer composites and self-healing
- Advanced Polymer Synthesis and Characterization
- 3D Printing in Biomedical Research
- Synthetic Organic Chemistry Methods
- Bullying, Victimization, and Aggression
- Cellular Mechanics and Interactions
- Dental materials and restorations
- Nanofabrication and Lithography Techniques
- Polydiacetylene-based materials and applications
- Photoreceptor and optogenetics research
- Hydrogels: synthesis, properties, applications
- Photochromic and Fluorescence Chemistry
University of Colorado Boulder
2019-2024
University of Colorado System
2019
To advance the capabilities of additive manufacturing, novel resin formulations are needed that produce high-fidelity parts with desired mechanical properties also amenable to recycling. In this work, a thiol–ene-based system incorporating semicrystallinity and dynamic thioester bonds within polymer networks is presented. It shown these materials have ultimate toughness values >16 MJ cm–3, comparable high-performance literature precedents. Significantly, treatment excess thiols facilitates...
This work examined and quantitatively predicted the degradation of thioester-containing networks facilitated by base-catalyzed thiol–thioester exchange. A statistical model was developed that incorporated polymer structure, exchange reaction kinetics, mass gain resulting from dynamic bond exchange, this compared to loss studies. Experimental results matched predictions, showing times could be controlled 2.5 12 h with optimal conditions varying free thiol butyl 3-mercaptopropionate...
Abstract Biofabrication allows for the templating of structural features in materials on cellularly-relevant size scales, enabling generation tissue-like structures with controlled form and function. This is particularly relevant growing organoids, where application biochemical biomechanical stimuli can be used to guide assembly differentiation stem cells architectures similar parent tissue or organ. Recently, ablative laser-scanning techniques was create 3D overhang collagen hydrogels at...
Photopolymerizable semicrystalline thermoplastics resulting from thiol-ene polymerizations were formed via fast and achieved excellent mechanical properties. These materials have been shown to produce desirable for additive manufacturing (3D printing), especially recyclable printing investment casting. However, while well-resolved prints previously with the thermoplastics, remarkable elongation at break (ϵmax) toughness (T) attained in bulk not realized 3D printed components (ϵmax,bulk ~...
The oligomeric structure of thioester-based covalent adaptable networks (CANs) was used to tune the bulk degradation thioester via a thiol–thioester exchange (TTE) reaction. A statistical kinetic model for developed that considered reaction rate, number links within oligomers, and dispersity these oligomer lengths. Model predictions indicated oligomers impacted rate by as much 10-fold, while narrowing up 2-fold. To evaluate with experimental studies, were synthesized, photocured into films,...
Stimuli-responsive degradation of hydrogels has established and emerging utilities ranging from controlled release biological products to sacrificial molding. Although covalent adaptable networks are particularly amenable for these applications, their kinetics have yet be clearly elucidated in swollen material systems. In this work, the thiol–thioester exchange reaction cross-linked poly(ethylene glycol) (PEG) is characterized determine relative effects thiol concentration, pKa, pH on...
Photocurable thiol-norbornene resins featuring triazole-embedded norbornene monomers were developed, and the photopolymerized networks showed good to superior ductility in glassy state with elongation-at-break ranging from 130 290% tensile toughness as high 57 MJ/m3, demonstrating value of triazoles forming tough, networks. Retained was observed two triazole/thiol-norbornene after physical aging at ambient temperature for 24 h, presumably due mechanical rejuvenation under uniaxial straining,...
Abstract Two‐stage polymerizing‐then‐degrading networks are achieved by exposure to a single near UV light source, sequentially performing thiol–ene photopolymerization and radical‐mediated thioaminal scission. To understand the mechanisms involved, synthesis of model small molecules shows photo‐activated scission produces thioamide moieties, identifiable distinct NMR singlets at 3.29 3.26 ppm Fourier Transform IR (FTIR) peak ≈1530 cm −1 . The process is proposed occur via ß‐scission carbon...