Article
Polymer Science
Loic Buchon, Jean-Michel Becht, Laurent Rubatat, Wei Wang, Hua Wei, Pu Xiao, Jacques Lalevee
Summary: This research synthesized and characterized four potential phosphine oxide photoinitiators and evaluated their efficiency in photopolymerization at 405 nm wavelength. Two of the obtained photoinitiators showed better performance than the widely used commercial photoinitiator. Additionally, one of the synthesized photoinitiators was successfully used in 3D printing of thermoplastics and exhibited lower cytotoxicity compared to the benchmark structure.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Polymer Science
Timur Borjigin, Guillaume Noirbent, Didier Gigmes, Pu Xiao, Frederic Dumur, Jacques Lalevee
Summary: In this study, a ligand and four copper complexes were found to exhibit excellent photosensitivity in various photoinitiating systems, particularly in the free radical polymerization and cationic polymerization processes. By investigating the performance of different photoinitiating systems, better support for 3D printing experiments was achieved.
EUROPEAN POLYMER JOURNAL
(2022)
Review
Polymer Science
H. Lai, X. Peng, L. Li, D. Zhu, P. Xiao
Summary: This review article focuses on the recent progress in the development of novel monomers for photopolymerization, including free radical polymerization, thiol-ene polymerization, and ring-opening cationic polymerization. The article also discusses recent innovations in photo-controlled reaction types for photopolymer network formation. This provides researchers in the field of functional photopolymer materials with an up-to-date survey and inspiration.
PROGRESS IN POLYMER SCIENCE
(2022)
Article
Polymer Science
Dominika Krok, Wiktoria Tomal, Alexander J. Knight, Alexander I. Tartakovskii, Nicholas T. H. Farr, Wiktor Kasprzyk, Joanna Ortyl
Summary: In this study, different types of carbon dots based on citric acid were synthesized and purified with an efficient method. The structural and optical characteristics were compared to commercially available graphene quantum dots, and the mechanism of their action in photopolymerization processes was evaluated. The obtained materials showed good performance in developing effective photoinitiating systems for 3D printing applications. The morphology and chemical composition of hydrogel printouts were characterized extensively using SEM, AFM, Nano-FTIR, and s-SNOM.
Article
Polymer Science
Piaoyi Chen, Yanfang Zhou, Qiuxia Li, Qinglin Xiao, Yingying Lun, Yugang Huang, Guodong Ye
Summary: A novel mechanism for photopolymerization, called photodriven radical-mediated [3+2] cyclopolymerization (PRMC), was proposed based on theoretical calculations and experimental measurements. This method has a low activation energy and can proceed spontaneously, allowing for polymerization of inert monomers at low temperatures.
Article
Dentistry, Oral Surgery & Medicine
Monika Topa-Skwarczynska, Magdalena Jankowska, Alicja Gruchala-Halat, Filip Petko, Mariusz Galek, Joanna Ortyl
Summary: This article aims to develop new generation dental composites that have improved performance compared to current dental fillings on the market, and to investigate the impact of new initiating systems on parameters such as degree of cure, hardness, color, and shrinkage. The effectiveness of the developed initiating systems was verified through spectroscopic, electrochemical, and kinetic studies using the real-time FT-IR method. The experiments demonstrated that the composite containing 3-SCH3Ph-Q, IOD, MDEA, nanometric silica, and a bonding agent achieved a cure rate of over 90% after just 1 cycle of dental lamp exposure (30 s), a hardness of 82 & PLUSMN; 4 on the Shore Scale after curing, and a polymerization shrinkage of less than 2.8%.
Review
Chemistry, Multidisciplinary
Zilong Wu, Cyrille Boyer
Summary: Near-infrared (NIR) light-induced reversible deactivation radical polymerization (NIR-RDRP) is an effective technique for preparing functional polymer materials using light energy. This review comprehensively summarizes the mechanisms and applications of NIR-RDRP systems.
Article
Chemistry, Multidisciplinary
Bianka Sieredzinska, Qi Zhang, Keimpe J. van den Berg, Jitte Flapper, Ben L. Feringa
Summary: A simple and general strategy for constructing photo-crosslinkable polymers by introducing sidechain 1,2-dithiolanes based on natural thioctic acid is presented. The disulfide five-membered rings act as both light-absorbing and dynamic covalent crosslinking units, enabling efficient photo-crosslinking and reversible chemical decrosslinking of polydimethylsiloxane polymers.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Yang Zhou, Shantao Han, Yu Gu, Mao Chen
Summary: The study developed a computer-aided droplet-flow polymerization based on photo-controlled reversible-deactivation radical polymerization (photo-RDRP) to synthesize gradient copolymers with tunable sequential arrangements. These gradient copolymers exhibit unique thermal properties and stimulus responsiveness compared to random and block copolymers, with the ability to regulate glass transition behavior through gradient tendency.
SCIENCE CHINA-CHEMISTRY
(2021)
Article
Polymer Science
Magdalena Jankowska, Anna Chachaj-Brekiesz, Klaudia Trembecka-Wojciga, Anna Jarzebska, Monika Topa-Skwarczynska, Maciej Pilch, Joanna Ortyl
Summary: This study presents the suitability of new derivatives, 9-[(E)-2-phenyl]anthracene and 9-[(E)-2-phenyl]phenanthrene, as photosensitizers for initiating various types of photopolymerization processes. The compounds were tested for cationic, radical, and hybrid photopolymerization and also for the addition of nanoparticles to obtain photo-curable nanocomposites. The combination of anthracene and phenanthrene derivatives with iodonium salt showed improved initiation efficiency. Additionally, the suitability of these derivatives in 3D printing applications using low-budget devices was tested.
Article
Chemistry, Multidisciplinary
Ceren Kutahya, Yingxiang Zhai, Shujun Li, Shouxin Liu, Jian Li, Veronika Strehmel, Zhijun Chen, Bernd Strehmel
Summary: Carbon nanodots (CDs) from different biomass show varying activities in sensitizing photo-induced reactions, and also demonstrate efficiency in free radical polymerization processes. The time-resolved fluorescence measurements revealed the presence of multiple emitting species contributing to the reactivity of excited states.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Wiktoria Tomal, Tomasz Swiergosz, Maciej Pilch, Wiktor Kasprzyk, Joanna Ortyl
Summary: This study investigates the application of citric acid-based carbon dots as efficient photosensitizers for initiating light-induced cationic polymerization, showing their potential in various polymerization reactions, including 3D printing. Carbon dots are found to be intriguing nano-photoinitiating catalysts with extraordinary properties under visible light.
Article
Chemistry, Physical
Giuseppe Trusiano, Alessandra Vitale, Jason Pulfer, Josiah Newton, Christine Joly-Duhamel, Chadron M. Friesen, Roberta Bongiovanni
Summary: Several difunctional oligomers were synthesized by functionalizing perfluoropolyalkylether (PFPAE) chains with different vinyl ethers and epoxides end-groups. Despite low yield and average functionality, the functionalized PFPAE oligomers showed success in photo-induced cationic polymerization processes, producing transparent and soft films. The influences of fluorinated chains, various end-groups on photopolymerization process, as well as their chemical stability, thermal degradation, and surface properties were investigated.
COLLOID AND POLYMER SCIENCE
(2021)
Article
Polymer Science
Hadi Bakhshi, Guanxing Kuang, Franziska Wieland, Wolfdietrich Meyer
Summary: The photo-curing kinetics and mechanical properties of urethane-acrylate-based photo-inks were evaluated in this study. It was found that the photopolymerization of urethane-dimethacrylate was temperature dependent, while the photopolymerization of urethane-acrylate was independent of temperature. The composition of the monomer mixture also influenced the photopolymerization rate and conversion, as well as the glass transition temperature and mechanical strength of the cured samples.
Review
Polymer Science
Lucie Pierau, Christine Elian, Jun Akimoto, Yoshihiro Ito, Sylvain Caillol, Davy-Louis Versace
Summary: This review highlights the increasing importance of cationic photopolymerization combined with bio-based photopolymerizable monomers. It serves as a guide for academic teams and industries to synthesize environmentally safe materials while reducing environmental impacts and toxicity.
PROGRESS IN POLYMER SCIENCE
(2022)
Article
Polymer Science
Raffael Wolff, Katharina Ehrmann, Patrick Knaack, Konstanze Seidler, Christian Gorsche, Thomas Koch, Juergen Stampfl, Robert Liska
Summary: This study reports the direct 3D printing of phenoplasts using Hot Lithography, a stereolithography-based 3D printing technology at elevated temperatures. Bubble-free specimens were obtained by suitable formulations and post-curing, enabling simple production of complicated structures.
Editorial Material
Polymer Science
Kurt Dietliker, Robert Liska, Marco Sangermano
Article
Polymer Science
Markus Lunzer, Boris Maryasin, Tommaso Zandrini, Stefan Baudis, Aleksandr Ovsianikov, Robert Liska
Summary: Photolabile groups are important components in photo-responsive polymers. Disulfides can be used for facile crosslinking and localized cleavage by two-photon irradiation, but their formation is challenging. The study identifies a reactive lead compound and investigates the effects of the molecular linker structure on hydrogel stability.
Article
Polymer Science
Patrick Steinbauer, Robert Liska, Stefan Baudis
Summary: Vinyl ester-based monomers have shown promise as alternatives to (meth)acrylates in radical photopolymerization due to their lower irritancy and cytotoxicity. Their increasing importance is attributed to cost-efficient synthetic production methods and improved material properties, particularly when copolymerized with other monomers. Studies on the copolymerization behavior of vinyl ester with norbornene, allyl ether and allyl ester have provided valuable insights into the polymer network of these copolymers.
POLYMER INTERNATIONAL
(2022)
Article
Polymer Science
Johannes Steindl, Katharina Ehrmann, Christian Gorsche, Ching-Chung Huang, Thomas Koch, Patrick Steinbauer, Andreas Rohatschek, Orestis G. Andriotis, Philipp J. Thurner, Alexander Prado-Roller, Juergen Stampfl, Robert Liska
Summary: The transfer of ABS microstructure to photopolymers via a designed monomer system has been achieved, resulting in new materials with high toughness.
POLYMER INTERNATIONAL
(2022)
Article
Polymer Science
Markus Kury, Katharina Ehrmann, Christian Gorsche, Peter Dorfinger, Thomas Koch, Jurgen Stampfl, Robert Liska
Summary: By adjusting the radical curing mechanism using difunctional vinyl sulfonate esters, the final material properties of acrylate networks can be modified to obtain toughened 3D structured materials. The resulting materials show improved thermomechanical behavior compared to those regulated by state-of-the-art reagents such as thiols, with reduced shrinkage stress, warpage, higher conversion, and glass transition temperature.
POLYMER INTERNATIONAL
(2022)
Article
Polymer Science
Barbara Dellago, Altan Alpay Altun, Robert Liska, Stefan Baudis
Summary: Vinyl esters (VEs) have been extensively studied as monomers for additive manufacturing in tissue engineering due to their low cytotoxicity, good biocompatibility, and favorable degradation behavior. However, crosslinked VEs have poor mechanical properties, especially brittleness. A previous study found that covalently incorporating high molecular weight additives into the vinyl ester-thiol network can overcome this issue. In this work, poly(epsilon-caprolactone)-based additives modified with photopolymerizable end groups were used to improve the mechanical properties, specifically toughness, and to enable application in digital light processing stereolithography. Different toughness-enhancing additives and their effects on photochemical and (thermo)mechanical characteristics were investigated, as well as the impact of commercial flexible and synthesized rigid thiols on these properties. The results showed that the covalently incorporated toughness enhancers significantly improved the mechanical properties, particularly tensile toughness, without sacrificing photoreactivity.
JOURNAL OF POLYMER SCIENCE
(2023)
Correction
Polymer Science
Benjamin Grob, Benedikt Frieser, Robert Liska, Yohann Catel
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Katharina Gallas, Dominik Wohlmuth, Zhiquan Li, Aliasghar Ajami, Aleksandr Ovsianikov, Robert Liska, Christian Slugovc
Summary: This study reports the synthesis of two dye-labeled azides through de-symmetrization using a copper (I)-catalyzed alkyne-azide cycloaddition (CuAAC) method. Dansyl derivative and perylene diimide derivative with alkyne functional groups were employed as the fluorescent dyes. The photo-physical properties of these dye dyads were described, and their performance in multi-photon grafting onto polyethylene glycol-based hydrogels was investigated. It was found that the dansyl-conjugated BAC derivative was suitable for multi-photon grafting with lasers operating at 800 nm, while the perylene diimide-bearing dye did not yield the desired result.
MONATSHEFTE FUR CHEMIE
(2023)
Article
Chemistry, Applied
Stephan Schandl, Thomas Koch, Juergen Stampfl, Katharina Ehrmann, Robert Liska
Summary: Aliphatic polycarbonates are highly regarded for being sustainable, biodegradable, and biocompatible. Recently, photobase generators have made cyclic carbonates available for light-induced anionic ring-opening polymerization, leading to the formation of pure aliphatic polycarbonate networks. The polymerization mechanism was investigated using photo-DSC and photorheology on synthesized cyclic carbonates. Different ratios of reactive diluent to crosslinker were tested to obtain materials with tunable mechanical properties.
REACTIVE & FUNCTIONAL POLYMERS
(2023)
Article
Chemistry, Applied
Lisa Staubmann, Agnes Mistlberger-Reiner, El Mehdi Raoui, Gertrude Brunner, Lisa Sinawehl, Marion Winter, Robert Liska, Marc Pignitter
Summary: This study investigates the stabilizing effects of pectin, guar gum, locust bean gum, and their combinations on ready-to-drink beverages containing 7% orange juice. Results show that in beverages with larger juice particles (0.6-200 μm), using 2.5 g pectin and 2.5 g guar gum per kg base is most suitable for stabilizing turbidity, while in beverages with smaller juice particles (0.5-120 μm), using 2 g pectin or 2.5 g pectin and 2.5 g locust bean gum per kg base can maintain stability. The combination of hydrocolloids has greater effects on long-term storage stability of the beverages compared to individual stabilizers.
FOOD HYDROCOLLOIDS
(2023)
Article
Engineering, Manufacturing
Viola Hobiger, Anna-Lea Kutsch, Juergen Stampfl, Robert Liska, Stefan Baudis, Peter Krajnc
Summary: A highly reactive thiol-ene high internal phase emulsion was developed for light-driven additive manufacturing, resulting in highly porous customizable poly(high internal phase emulsion) materials. The formulation facilitates short irradiation times and low amounts of photoinitiator, while avoiding the need for harmful solvents. The addition of a selected thiol as a chain-transfer agent improves the brittleness of the acrylate-based system and potential oxygen inhibition, producing printed layers with a thickness<50 μm and an average pore size<5 μm.
3D PRINTING AND ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Roland Taschner, Thomas Koch, Raffael Wolff, Juergen Stampfl, Robert Liska, Patrick Knaack
Summary: Sulfonium hexafluorophosphates and perfluorinated tetraphenylborates are established initiators in cationic photopolymerization. The cyanide-ligated borane-based photoinitiator B2 outperforms commercial initiators in terms of molecular weight, cost, and reactivity. In addition, B2 shows excellent thermal and storage stability, and can be sensitized by anthracene derivatives. When used in hot lithography at 90°C, B2 exhibits superior layer quality and coloration compared to existing sulfonium initiators.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Larissa Alena Ruppitsch, Jakob Ecker, Thomas Koch, Katharina Ehrmann, Juergen Stampfl, Robert Liska
Summary: Supramolecular polymers play a significant role in influencing dynamic mechanical properties in slightly crosslinked polymer networks. The introduction of 2-ureido-4[1H]-pyrimidinones (UPy) as supramolecular building blocks in photopolymerizable systems brings about dynamic behavior. This study investigates the impact of UPy-motif on reactivity and (thermo)mechanical properties through various testing methods. Furthermore, the UPy-based photopolymerizable system is successfully applied in Hot Lithography printing to create complex 3D-printed parts with high precision.
JOURNAL OF POLYMER SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Roland Taschner, Thomas Koch, Raffael Wolff, Jurgen Stampfl, Robert Liska, Patrick Knaack
Summary: Sulfonium hexafluorophosphates and perfluorinated tetraphenylborates are commonly used initiators in cationic photopolymerization and have been applied in 3D-printing at high temperatures. The cyanide-ligated borane-based photoinitiator B2 shows higher reactivity and lower cost compared to other borates. B2 exhibits excellent performance in epoxy monomer conversions at a wide range of temperatures. In addition, B2-based formulations are stable and can be sensitized by anthracene derivatives. B2 also outperforms existing sulfonium initiators in terms of layer quality and coloration in hot lithography.
ACS APPLIED POLYMER MATERIALS
(2023)
