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
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
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
James B. Young, Jared Bowman, Cabell B. Eades, Alexander J. Wong, Brent S. Sumerlin
Summary: Controlled radical polymerization techniques allow for the synthesis of polymers with specific molecular weights and architectures. In this study, the role of light in triggering thermal depolymerization of polymers synthesized through reversible-addition-fragmentation chain-transfer (RAFT) polymerization was investigated. By targeting specific electronic transitions, the depolymerization efficiency was enhanced.
Article
Engineering, Chemical
Robert Setter, Stefan Schmoelzer, Natalie Rudolph, Elena Moukhina, Katrin Wudy
Summary: This study investigates the utilization of different kinetic models based on experimentally determined calorimetric results of different acrylate systems. The goal is to determine a holistic model that successfully describes the simultaneous dependency of the curing behavior on temperature and UV intensity. Two consecutive modeling strategies are investigated: a single measurement analysis followed by a clustered measurement analysis. In both cases, models based on the Kamal-Sourour method provide superior coefficients of determination above 0.99.
POLYMER ENGINEERING AND SCIENCE
(2023)
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: The synthesis and polymerization behavior of four different monofunctional vinyl cyclopropane (VCP) derivatives were investigated. The study found that different VCPs have varying abilities to form hydrogen bonds in their side chains, leading to preorganization and potentially faster polymerization. Although VCPs capable of hydrogen bonding did not show significant differences, a general effect of hydrogen bonds on polymerization behavior was observed.
Article
Polymer Science
Joao R. C. Costa, Joana R. Gois, Jose R. Fernandes, Krzysztof Matyjaszewski, Jorge F. J. Coelho, Armenio C. Serra
Summary: This study presents a simple photo-controlled iodine transfer polymerization system using methacrylate monomers, solvent, and initiator under violet and sunlight irradiation with good control over the polymerization process. The system does not require additional photocatalysts or iodide salts and provides tight control over activation and deactivation. The polymerization system under sunlight extends to several methacrylate monomers in a well-controlled manner.
Article
Chemistry, Multidisciplinary
Zilong Wu, Wenbo Fang, Chenyu Wu, Nathaniel Corrigan, Tong Zhang, Sihao Xu, Cyrille Boyer
Summary: In this study, we report an aqueous and near-infrared light mediated photoinduced reversible addition-fragmentation chain transfer polymerization system. With the high catalytic efficiency and excellent oxygen tolerance, this system allows fast synthesis of well-controlled polymers, even in the presence of non-transparent barriers. We further demonstrate the synthesis of polymeric nanoparticles with consistent morphologies through thick barriers, utilizing the advantages of NIR wavelengths.
Article
Polymer Science
Selma Usturk, Ergul Mutlu Altundag, Elvan Yilmaz
Summary: Pullulan/polyHEMA cryogels were synthesized using ECH and EGDMA as crosslinkers, exhibiting different microstructures. The IPN sample showed a more hydrophobic surface and smaller pore size compared to the graft copolymer. Gravimetric studies revealed the degradability of the cryogels in aqueous media, and cell viability tests demonstrated non-toxicity and promotion of cell proliferation for colon carcinoma cells.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Zilong Wu, Tong Zhang, Xiaobing Shi, Nathaniel Corrigan, Gervase Ng, Cyrille Boyer
Summary: In this study, a photoinduced reversible addition-fragmentation chain transfer (photo-RAFT) polymerization system mediated by tetrasulfonated zinc phthalocyanine (ZnPcS4-) in the presence of peroxides was reported. This system displayed fast polymerization rates and high oxygen tolerance, enabling the preparation of hydrogels. By utilizing the enhanced penetration of near-infrared (NIR) light, photoinduced gelation could be effectively achieved through non-transparent biological barriers. Moreover, the RAFT agents embedded in these hydrogel networks could be reactivated on-demand, facilitating the healing of hydrogels under NIR light irradiation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Polymer Science
I Zaborniak, P. Chmielarz
Summary: Radical polymerization techniques utilizing naturally occurring substances, such as riboflavin, are being rapidly developed towards more sustainable and environmentally friendly approaches. Riboflavin's unique structure and biological activity make it an excellent target for radical polymerization, with its versatile properties that allow for easy modification to incorporate additional functional groups. Recent advances in utilizing riboflavin structure to mediate free radical polymerization and controlled polymerization techniques offer environmentally friendly and easily scalable methods for the preparation of functional polymer materials with diverse applications.
EUROPEAN POLYMER JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Tadashi Kanbara, Mizuki Arase, Miyu Tanaka, Airi Yamaguchi, Koto Tagami, Tomoko Yajima
Summary: In this study, synthesis methods for fluorine-containing polymers were developed using photoirradiation halogen bonding. Sequential polymerization resulted in fluoroalkyl-alkyl-alternating polymers, while chain polymerization produced polymers with perfluoroalkyl terminals. Block polymers were also synthesized through successive chain polymerization.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Review
Chemistry, Applied
Nina Guy, Olivia Giani, Sebastien Blanquer, Julien Pinaud, Jean-Jacques Robin
Summary: Photopolymerization is gaining interest in both industrial and academic fields due to its high reaction kinetics, low emissions of organic solvents, and reduced shrinking stress. This method has mainly been developed for radical polymerization of vinyl monomers and to a lesser extent for ring-opening polymerization (ROP). With the emergence of new initiating systems, the photopolymerization of various cyclic monomers has expanded beyond epoxides, which were the first monomers polymerized by cationic ring-opening polymerization (CROP).
PROGRESS IN ORGANIC COATINGS
(2021)
Article
Polymer Science
Alamelu Suriya Subramanian, Xiao 'Matthew' Hu
Summary: The photosensitivity of nanoparticulate polydopamine and polydopamine coated multiwalled carbon nanotubes was investigated in relation to the photopolymerization of epoxy monomers. It was found that the inclusion of PDA/MWCNT nanohybrid significantly increased the polymerization speed and conversion. Furthermore, the covalent coated PDA/MWCNT nanohybrids acted as both photosensitizer/co-initiator and mechanical reinforcement for the epoxy matrix. This hybridized sensitizers/co-initiators have the potential to be applied in UV-blocking additive-dependent VAT-type 3D printing technologies.
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
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)
Article
Polymer Science
Benjamin Grob, Benedikt Frieser, Robert Liska, Yohann Catel
Summary: Polymerization shrinkage and shrinkage stress are crucial issues in dental restorations. Addition fragmentation chain transfer agents (AFCT agents) are effective in reducing shrinkage stress. Four novel polymerizable allyl sulfides were synthesized and evaluated in dental composites. AFCT-based composites showed good performance.
EUROPEAN POLYMER JOURNAL
(2022)
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
Materials Science, Multidisciplinary
Antonella Fantoni, Thomas Koch, Stefan Baudis, Robert Liska
Summary: The development of bio-based epoxy resins from aliphatic biomass and lignin has seen rapid growth. However, the polymerization behavior and resulting properties of these resins when co-cured with alcohols have not been extensively investigated. In this study, the polymerization of bio-based epoxides with alcohols using imidazoles as catalysts was analyzed, revealing a controlled co-polymerization. The resulting thermosets exhibited tunable glass transition temperature and high tensile toughness, making them potential candidates for industrial applications.
ACS APPLIED POLYMER MATERIALS
(2022)
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
Chemistry, Physical
Raffael Wolff, Patrick Knaack, Konstanze Seidler, Christian Gorsche, Thomas Koch, Juergen Stampfl, Robert Liska
Summary: Polycyanurates have excellent thermomechanical properties due to their unique triazine structure and phenolic chains. A new method of additive manufacturing using photo-induced catalytic poly-trimerization and Hot Lithography allows for the production of pure polycyanurates without relying on matrix polymers or fillers. The 3D printed structures exhibit thermomechanical values that have rarely been attainable before, making this process a promising opportunity for high-performance polymer production in additive manufacturing.
JOURNAL OF MATERIALS CHEMISTRY A
(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)
Meeting Abstract
Cell & Tissue Engineering
Philip Schwarzl, Katharina Ehrmann, Christian Grasl, Helga Bergmeister, Heinrich Schima, Bruno Podesser, Robert Liska, Stefan Baudis
TISSUE ENGINEERING PART A
(2022)
