Publications
⌵
2024
17.
Petelinšek, N.; Mommer, S.
Tough Hydrogels for Load-Bearing Applications Journal Article
In: Advanced Science, pp. 2307404, 2024.
@article{nokey,
title = {Tough Hydrogels for Load-Bearing Applications},
author = {N. Petelinšek and S. Mommer},
doi = {10.1002/advs.202307404},
year = {2024},
date = {2024-01-15},
urldate = {2024-01-15},
journal = {Advanced Science},
pages = {2307404},
abstract = {Abstract Tough hydrogels have emerged as a promising class of materials to target load-bearing applications, where the material has to resist multiple cycles of extreme mechanical impact. A variety of chemical interactions and network architectures are used to enhance the mechanical properties and fracture mechanics of hydrogels making them stiffer and tougher. In recent years, the mechanical properties of tough, high-performance hydrogels have been benchmarked, however, this is often incomplete as important variables like water content are largely ignored. In this review, the aim is to clarify the reported mechanical properties of state-of-the-art tough hydrogels by providing a comprehensive library of fracture and mechanical property data. First, common methods for mechanical characterization of such high-performance hydrogels are introduced. Then, various modes of energy dissipation to obtain tough hydrogels are discussed and used to categorize the individual datasets helping to asses the material's (fracture) mechanical properties. Finally, current applications are considered, tough high-performance hydrogels are compared with existing materials, and promising future opportunities are discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Tough hydrogels have emerged as a promising class of materials to target load-bearing applications, where the material has to resist multiple cycles of extreme mechanical impact. A variety of chemical interactions and network architectures are used to enhance the mechanical properties and fracture mechanics of hydrogels making them stiffer and tougher. In recent years, the mechanical properties of tough, high-performance hydrogels have been benchmarked, however, this is often incomplete as important variables like water content are largely ignored. In this review, the aim is to clarify the reported mechanical properties of state-of-the-art tough hydrogels by providing a comprehensive library of fracture and mechanical property data. First, common methods for mechanical characterization of such high-performance hydrogels are introduced. Then, various modes of energy dissipation to obtain tough hydrogels are discussed and used to categorize the individual datasets helping to asses the material’s (fracture) mechanical properties. Finally, current applications are considered, tough high-performance hydrogels are compared with existing materials, and promising future opportunities are discussed.
2023
16.
S. Mommer, N. Warner; Lienert, C.
γ-Functional Iminiumthiolactones for the Single and Double Modification of Peptides Journal Article
In: Bioconjugate Chemistry, 2023.
@article{nokey,
title = {γ-Functional Iminiumthiolactones for the Single and Double Modification of Peptides},
author = {S. Mommer, N. Warner and C. Lienert},
doi = {10.1021/acs.bioconjchem.3c00424},
year = {2023},
date = {2023-11-27},
urldate = {2023-11-27},
journal = {Bioconjugate Chemistry},
abstract = {Thiolactones (TL) can be readily incorporated into polymeric materials and have been extensively used as a ligation strategy despite their limited reactivity toward amine-containing substrates. Comparatively, iminiumthiolactones (ITL) are much more reactive, yet to this day, only the nonsubstituted ITL known as Traut’s reagent is commercially available and used. In this work, we advance current TL/ITL chemistry by introducing reactive side groups to the ITL heterocycle in the γ-position, which can be orthogonally modified without affecting the ITL heterocycle itself. To study the reactivity of γ-functional ITLs, we subject one of our derivatives (γ-allyl-functional ITL 3b) to model reactions with several peptides and a chosen protein (lysozyme C). Using mild reaction conditions, we successfully demonstrate that the γ-functional ITL exhibits orthogonal and enhanced reactivity in a single or double modification while introducing a new functional handle to the biological substrate. We believe that γ-functional ITLs will advance the original Traut chemistry and open promising opportunities for the bioconjugation of biological building blocks to existing functional molecules, polymers, and materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Thiolactones (TL) can be readily incorporated into polymeric materials and have been extensively used as a ligation strategy despite their limited reactivity toward amine-containing substrates. Comparatively, iminiumthiolactones (ITL) are much more reactive, yet to this day, only the nonsubstituted ITL known as Traut’s reagent is commercially available and used. In this work, we advance current TL/ITL chemistry by introducing reactive side groups to the ITL heterocycle in the γ-position, which can be orthogonally modified without affecting the ITL heterocycle itself. To study the reactivity of γ-functional ITLs, we subject one of our derivatives (γ-allyl-functional ITL 3b) to model reactions with several peptides and a chosen protein (lysozyme C). Using mild reaction conditions, we successfully demonstrate that the γ-functional ITL exhibits orthogonal and enhanced reactivity in a single or double modification while introducing a new functional handle to the biological substrate. We believe that γ-functional ITLs will advance the original Traut chemistry and open promising opportunities for the bioconjugation of biological building blocks to existing functional molecules, polymers, and materials.
15.
Villarón, David; Bos, Jasper E.; Kohl, Fabien; Mommer, Stefan; Jong, Jorn; Wezenberg, Sander J.
Photoswitchable Bis(amidopyrroles): Modulating Anion Transport Activity Independent of Binding Affinity Journal Article
In: The Journal of Organic Chemistry, 2023, ISSN: 0022-3263, (doi: 10.1021/acs.joc.3c01018).
@article{RN3604,
title = {Photoswitchable Bis(amidopyrroles): Modulating Anion Transport Activity Independent of Binding Affinity},
author = {David Villarón and Jasper E. Bos and Fabien Kohl and Stefan Mommer and Jorn Jong and Sander J. Wezenberg},
url = {https://doi.org/10.1021/acs.joc.3c01018},
doi = {10.1021/acs.joc.3c01018},
issn = {0022-3263},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {The Journal of Organic Chemistry},
abstract = {Toward photocontrol of anion transport across the bilayer membrane, stiff-stilbene, which has dimethyl substituents in the five-membered rings, is functionalized with amidopyrrole units. UV–vis and 1H NMR studies show high photostability and photoconversion yields. Where the photoaddressable (E)- and (Z)-isomers exhibit comparable binding affinities, as determined by 1H NMR titrations, fluorescence-based transport assays reveal significantly higher transport activity for the (Z)-isomers. Changing the binding affinity is thus not a necessity for modulating transport. Additionally, transport can be triggered in situ by light.},
note = {doi: 10.1021/acs.joc.3c01018},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Toward photocontrol of anion transport across the bilayer membrane, stiff-stilbene, which has dimethyl substituents in the five-membered rings, is functionalized with amidopyrrole units. UV–vis and 1H NMR studies show high photostability and photoconversion yields. Where the photoaddressable (E)- and (Z)-isomers exhibit comparable binding affinities, as determined by 1H NMR titrations, fluorescence-based transport assays reveal significantly higher transport activity for the (Z)-isomers. Changing the binding affinity is thus not a necessity for modulating transport. Additionally, transport can be triggered in situ by light.
2022
14.
Mommer, Stefan; Sokołowski, Kamil; Olesińska, Magdalena; Huang, Zehuan; Scherman, Oren A.
Supramolecular encapsulation of redox-active monomers to enable free-radical polymerisation Journal Article
In: Chemical Science, vol. 13, no. 30, pp. 8791-8796, 2022, ISSN: 2041-6520.
@article{RN3107,
title = {Supramolecular encapsulation of redox-active monomers to enable free-radical polymerisation},
author = {Stefan Mommer and Kamil Sokołowski and Magdalena Olesińska and Zehuan Huang and Oren A. Scherman},
url = {http://dx.doi.org/10.1039/D2SC02072F},
doi = {10.1039/D2SC02072F},
issn = {2041-6520},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Chemical Science},
volume = {13},
number = {30},
pages = {8791-8796},
abstract = {Extended polymeric structures based on redox-active species are of great interest in emerging technologies related to energy conversion and storage. However, redox-active monomers tend to inhibit radical polymerisation processes and hence, increase polydispersity and reduce the average molecular weight of the resultant polymers. Here, we demonstrate that styrenic viologens, which do not undergo radical polymerisation effectively on their own, can be readily copolymerised in the presence of cucurbit[n]uril (CB[n]) macrocycles. The presented strategy relies on pre-encapsulation of the viologen monomers within the molecular cavities of the CB[n] macrocycle. Upon polymerisation, the molecular weight of the resultant polymer was found to be an order of magnitude higher and the polydispersity reduced 5-fold. The mechanism responsible for this enhancement was unveiled through comprehensive spectroscopic and electrochemical studies. A combination of solubilisation/stabilisation of reduced viologen species as well as protection of the parent viologens against reduction gives rise to the higher molar masses and reduced polydispersities. The presented study highlights the potential of CB[n]-based host–guest chemistry to control both the redox behavior of monomers as well as the kinetics of their radical polymerisation, which will open up new opportunities across myriad fields.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Extended polymeric structures based on redox-active species are of great interest in emerging technologies related to energy conversion and storage. However, redox-active monomers tend to inhibit radical polymerisation processes and hence, increase polydispersity and reduce the average molecular weight of the resultant polymers. Here, we demonstrate that styrenic viologens, which do not undergo radical polymerisation effectively on their own, can be readily copolymerised in the presence of cucurbit[n]uril (CB[n]) macrocycles. The presented strategy relies on pre-encapsulation of the viologen monomers within the molecular cavities of the CB[n] macrocycle. Upon polymerisation, the molecular weight of the resultant polymer was found to be an order of magnitude higher and the polydispersity reduced 5-fold. The mechanism responsible for this enhancement was unveiled through comprehensive spectroscopic and electrochemical studies. A combination of solubilisation/stabilisation of reduced viologen species as well as protection of the parent viologens against reduction gives rise to the higher molar masses and reduced polydispersities. The presented study highlights the potential of CB[n]-based host–guest chemistry to control both the redox behavior of monomers as well as the kinetics of their radical polymerisation, which will open up new opportunities across myriad fields.
13.
Mommer, Stefan; Wezenberg, Sander J.
Anion-Induced Reversible Actuation of Squaramide-Crosslinked Polymer Gels Journal Article
In: ACS Applied Materials & Interfaces, vol. 14, no. 38, pp. 43711-43718, 2022, ISSN: 1944-8244.
@article{RN3117,
title = {Anion-Induced Reversible Actuation of Squaramide-Crosslinked Polymer Gels},
author = {Stefan Mommer and Sander J. Wezenberg},
url = {https://doi.org/10.1021/acsami.2c11136},
doi = {10.1021/acsami.2c11136},
issn = {1944-8244},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {ACS Applied Materials & Interfaces},
volume = {14},
number = {38},
pages = {43711-43718},
abstract = {Supramolecular anion binding to squaramide crosslinkers in poly(N,N-dimethylacrylamide) gel networks enhances swelling and allows reversible chemically driven actuation. The volume swelling ratio of the gels is shown to depend on both the type of anion and its concentration. 1H NMR and UV–vis titrations with the squaramide crosslinkers reveal a relationship between anion binding affinity and the concentration-dependent swelling behavior. Gel swelling is shown to be reversible, and by embedding a solid support into rod-shaped gels, soft actuators are fabricated that undergo forward and backward bending motion in response to changing anion concentration. The swelling and bending process, which is accompanied by intense green coloration of the gel, is achieved by using only low amounts of crosslinker. This macroscopic actuation achieved by anion binding to specific molecular entities in the polymer network will open new opportunities in the field of chemically responsive materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Supramolecular anion binding to squaramide crosslinkers in poly(N,N-dimethylacrylamide) gel networks enhances swelling and allows reversible chemically driven actuation. The volume swelling ratio of the gels is shown to depend on both the type of anion and its concentration. 1H NMR and UV–vis titrations with the squaramide crosslinkers reveal a relationship between anion binding affinity and the concentration-dependent swelling behavior. Gel swelling is shown to be reversible, and by embedding a solid support into rod-shaped gels, soft actuators are fabricated that undergo forward and backward bending motion in response to changing anion concentration. The swelling and bending process, which is accompanied by intense green coloration of the gel, is achieved by using only low amounts of crosslinker. This macroscopic actuation achieved by anion binding to specific molecular entities in the polymer network will open new opportunities in the field of chemically responsive materials.
2021
12.
Mommer, Stefan; Gehlen, David; Akagi, Takami; Akashi, Mitsuru; Keul, Helmut; Möller, Martin
Thiolactone-Functional Pullulan for In Situ Forming Biogels Journal Article
In: Biomacromolecules, vol. 22, no. 10, pp. 4262-4273, 2021.
@article{RN2844,
title = {Thiolactone-Functional Pullulan for In Situ Forming Biogels},
author = {Mommer, Stefan and Gehlen, David and Akagi, Takami and Akashi, Mitsuru and Keul, Helmut and Möller, Martin},
doi = {10.1021/acs.biomac.1c00807},
year = {2021},
date = {2021-10-11},
urldate = {2021-10-11},
journal = {Biomacromolecules},
volume = {22},
number = {10},
pages = {4262-4273},
abstract = {Gelation in the presence of cells with minimum cytotoxicity is highly desirable for materials with applications in tissue engineering. Herein, the naturally occurring polysaccharide pullulan is functionalized with thiolactones that undergo ring-opening addition of amines. As a result, the modified pullulan can be cross-linked with diamines and/or amine-containing biological substrates enhancing the system's versatility (e.g., gelatin and cellbinding ligands GHK/GRGDS). Thiolactone degrees of substitution of 2.5 or 5.0 mol % are achieved, and respective hydrogels exhibit mesh sizes of 27.8 to 49.1 nm. Cell proliferation studies on chosen gels (G′ ≅ 500 Pa, over 14 days) demonstrate that for normal human dermal fibroblasts (NHDFs), both gelatin and GRGDS equally support cell proliferation, while in the case of hepatocytes (HepG2), the presence ofGRGDS and GHK improve cell proliferation 10-fold compared to gelatin. Cells remain viable and in one instance were successfully encapsulated by in situ gelation, altogether confirming the mild and biocompatible nature of this strategy to produce biogels using biologically active substrates as cross-linkers.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gelation in the presence of cells with minimum cytotoxicity is highly desirable for materials with applications in tissue engineering. Herein, the naturally occurring polysaccharide pullulan is functionalized with thiolactones that undergo ring-opening addition of amines. As a result, the modified pullulan can be cross-linked with diamines and/or amine-containing biological substrates enhancing the system’s versatility (e.g., gelatin and cellbinding ligands GHK/GRGDS). Thiolactone degrees of substitution of 2.5 or 5.0 mol % are achieved, and respective hydrogels exhibit mesh sizes of 27.8 to 49.1 nm. Cell proliferation studies on chosen gels (G′ ≅ 500 Pa, over 14 days) demonstrate that for normal human dermal fibroblasts (NHDFs), both gelatin and GRGDS equally support cell proliferation, while in the case of hepatocytes (HepG2), the presence ofGRGDS and GHK improve cell proliferation 10-fold compared to gelatin. Cells remain viable and in one instance were successfully encapsulated by in situ gelation, altogether confirming the mild and biocompatible nature of this strategy to produce biogels using biologically active substrates as cross-linkers.
2020
11.
McCune, Jade; Mommer, Stefan; Parkins, Chris; Scherman, Oren A.
Design principles for aqueous interactive materials: Lessons from small molecules and stimuli responsive systems Journal Article
In: Advanced Materials, vol. 32, no. 20, pp. 1906890, 2020.
@article{RN2210,
title = {Design principles for aqueous interactive materials: Lessons from small molecules and stimuli responsive systems},
author = {Jade McCune and Stefan Mommer and Chris Parkins and Oren A. Scherman},
doi = {10.1002/adma.201906890},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {Advanced Materials},
volume = { 32},
number = {20},
pages = {1906890},
abstract = {Interactive materials are at the forefront of current materials research with few examples in the literature. Researchers are inspired by nature to develop materials that can modulate and adapt their behavior in accordance with their surroundings. Stimuli-responsive systems have been developed over the past decades which, although often described as “smart,” lack the ability to act autonomously. Nevertheless, these systems attract attention on account of the resultant materials' ability to change their properties in a predicable manner. These materials find application in a plethora of areas including drug delivery, artificial muscles, etc. Stimuli-responsive materials are serving as the precursors for next-generation interactive materials. Interest in these systems has resulted in a library of well-developed chemical motifs; however, there is a fundamental gap between stimuli-responsive and interactive materials. In this perspective, current state-of-the-art stimuli-responsive materials are outlined with a specific emphasis on aqueous macroscopic interactive materials. Compartmentalization, critical for achieving interactivity, relies on hydrophobic, hydrophilic, supramolecular, and ionic interactions, which are commonly present in aqueous systems and enable complex self-assembly processes. Relevant examples of aqueous interactive materials that do exist are given, and design principles to realize the next generation of materials with embedded autonomous function are suggested.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Interactive materials are at the forefront of current materials research with few examples in the literature. Researchers are inspired by nature to develop materials that can modulate and adapt their behavior in accordance with their surroundings. Stimuli-responsive systems have been developed over the past decades which, although often described as “smart,” lack the ability to act autonomously. Nevertheless, these systems attract attention on account of the resultant materials’ ability to change their properties in a predicable manner. These materials find application in a plethora of areas including drug delivery, artificial muscles, etc. Stimuli-responsive materials are serving as the precursors for next-generation interactive materials. Interest in these systems has resulted in a library of well-developed chemical motifs; however, there is a fundamental gap between stimuli-responsive and interactive materials. In this perspective, current state-of-the-art stimuli-responsive materials are outlined with a specific emphasis on aqueous macroscopic interactive materials. Compartmentalization, critical for achieving interactivity, relies on hydrophobic, hydrophilic, supramolecular, and ionic interactions, which are commonly present in aqueous systems and enable complex self-assembly processes. Relevant examples of aqueous interactive materials that do exist are given, and design principles to realize the next generation of materials with embedded autonomous function are suggested.
2019
10.
Mommer, Stefan; Kurniadi, Juliana; Keul, Helmut; Möller, Martin
Formaldehyde-free curing of cotton cellulose fabrics in anhydrous media Journal Article
In: Journal of Applied Polymer Science, vol. 137, pp. 48371, 2019, ISSN: 0021-8995.
@article{RN2216,
title = {Formaldehyde-free curing of cotton cellulose fabrics in anhydrous media},
author = {Stefan Mommer and Juliana Kurniadi and Helmut Keul and Martin Möller},
url = {https://doi.org/10.1002/app.48371},
doi = {10.1002/app.48371},
issn = {0021-8995},
year = {2019},
date = {2019-01-01},
urldate = {2019-01-01},
journal = {Journal of Applied Polymer Science},
volume = {137},
pages = {48371},
abstract = {ABSTRACT The effect of formaldehyde-free curing on standard cotton cellulose fabrics in anhydrous media is studied. Different crosslinkers are applied via (1) a pad-cure-dry process (solid/liquid) and (2) in a vapor chamber (solid/gas). The performance of each crosslinker and set of conditions is assessed by measuring dry crease recovery angles, DCRAs. We find that in control samples (treatment without crosslinker) the DCRAs are altered depending on the solvent. Using DMF, carbonyldiimidazole shows the best DCRA (160.1°, 15° higher than the non-treated fabrics). In ethyl acetate, triglycidyl isocyanurate shows the highest DCRA (22° higher than the control). The most promising crosslinkers are applied with selected catalysts known from literature. Here, trigycidyl isocyanurate in combination with the superbase P4-t-Bu gives the best DCRA (35° higher than the control). Using the vapor-chemical finishing, divinylsulfone as crosslinker increases the DCRA to 162.7° (18° higher than non-treated fabrics). Hence, cotton cellulose fabrics can be successfully finished in anhydrous conditions. ? 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48371.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
ABSTRACT The effect of formaldehyde-free curing on standard cotton cellulose fabrics in anhydrous media is studied. Different crosslinkers are applied via (1) a pad-cure-dry process (solid/liquid) and (2) in a vapor chamber (solid/gas). The performance of each crosslinker and set of conditions is assessed by measuring dry crease recovery angles, DCRAs. We find that in control samples (treatment without crosslinker) the DCRAs are altered depending on the solvent. Using DMF, carbonyldiimidazole shows the best DCRA (160.1°, 15° higher than the non-treated fabrics). In ethyl acetate, triglycidyl isocyanurate shows the highest DCRA (22° higher than the control). The most promising crosslinkers are applied with selected catalysts known from literature. Here, trigycidyl isocyanurate in combination with the superbase P4-t-Bu gives the best DCRA (35° higher than the control). Using the vapor-chemical finishing, divinylsulfone as crosslinker increases the DCRA to 162.7° (18° higher than non-treated fabrics). Hence, cotton cellulose fabrics can be successfully finished in anhydrous conditions. ? 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48371.
9.
Tabet, Anthony; Mommer, Stefan; Vigil, Julian A.; Hallou, Clement; Bulstrode, Harry; Scherman, Oren A.
Mechanical Characterization of Human Brain Tissue and Soft Dynamic Gels Exhibiting Electromechanical Neuro-Mimicry Journal Article
In: Advanced Healthcare Materials, vol. 8, no. 10, pp. 1900068, 2019, ISSN: 2192-2640.
@article{RN1478,
title = {Mechanical Characterization of Human Brain Tissue and Soft Dynamic Gels Exhibiting Electromechanical Neuro-Mimicry},
author = {Anthony Tabet and Stefan Mommer and Julian A. Vigil and Clement Hallou and Harry Bulstrode and Oren A. Scherman},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adhm.201900068},
doi = {10.1002/adhm.201900068},
issn = {2192-2640},
year = {2019},
date = {2019-01-01},
urldate = {2019-01-01},
journal = {Advanced Healthcare Materials},
volume = {8},
number = {10},
pages = {1900068},
abstract = {Abstract Synthetic hydrogels are an important class of materials in tissue engineering, drug delivery, and other biomedical fields. Their mechanical and electrical properties can be tuned to match those of biological tissues. In this work, hydrogels that exhibit both mechanical and electrical biomimicry are reported. The presented dual networks consist of supramolecular networks formed from 2:1 homoternary complexes of imidazolium-based guest molecules in cucubit[8]uril and covalent networks of oligoethylene glycol-(di)methacrylate. The viscoelastic properties of human brain tissues are also investigated. The mechanical properties of the dual network gels are benchmarked against the human tissue, and it is found that they both are neuro-mimetic and exhibit cytocompatibility in a neural stem cell model.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Synthetic hydrogels are an important class of materials in tissue engineering, drug delivery, and other biomedical fields. Their mechanical and electrical properties can be tuned to match those of biological tissues. In this work, hydrogels that exhibit both mechanical and electrical biomimicry are reported. The presented dual networks consist of supramolecular networks formed from 2:1 homoternary complexes of imidazolium-based guest molecules in cucubit[8]uril and covalent networks of oligoethylene glycol-(di)methacrylate. The viscoelastic properties of human brain tissues are also investigated. The mechanical properties of the dual network gels are benchmarked against the human tissue, and it is found that they both are neuro-mimetic and exhibit cytocompatibility in a neural stem cell model.
2017
8.
Marquardt, Fabian; Mommer, Stefan; Lange, Justin; Jeschenko, Pascal M; Keul, Helmut; Möller, Martin
Homoserine lactone as a structural key element for the synthesis of multifunctional polymers Journal Article
In: Polymers, vol. 9, no. 4, pp. 130, 2017.
@article{RN2221,
title = {Homoserine lactone as a structural key element for the synthesis of multifunctional polymers},
author = {Fabian Marquardt and Stefan Mommer and Justin Lange and Pascal M Jeschenko and Helmut Keul and Martin Möller},
url = {https://doi.org/10.3390/polym9040130},
doi = {10.3390/polym9040130},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Polymers},
volume = {9},
number = {4},
pages = {130},
abstract = {The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino)-1-propylamine followed by quaternization with methyl iodide.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino)-1-propylamine followed by quaternization with methyl iodide.
7.
Mommer, Stefan; Keul, Helmut; Möller, Martin
One-Pot Synthesis of Amino Acid-Based Polyelectrolytes and Nanoparticle Synthesis Journal Article
In: Biomacromolecules, vol. 18, iss. 1, pp. 159-168, 2017, ISSN: 1525-7797.
@article{RN1002,
title = {One-Pot Synthesis of Amino Acid-Based Polyelectrolytes and Nanoparticle Synthesis},
author = {Stefan Mommer and Helmut Keul and Martin Möller},
url = {http://dx.doi.org/10.1021/acs.biomac.6b01420},
doi = {10.1021/acs.biomac.6b01420},
issn = {1525-7797},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Biomacromolecules},
volume = {18},
issue = {1},
pages = {159-168},
abstract = {In this manuscript, a biscyclic monomer with an epoxide and a thiolactone ring connected by a urethane bond is used for the synthesis of amino acid-functional polyelectrolytes. In a first step, lithium salts of amino acids react selectively with the thiolactone ring by ring-opening, formation of an amide bond, and a thiol group. In a second step and in the presence of a base a polymeric building block is formed by polyaddition of the thiolate to the epoxide ring. The reaction occurs at room temperature in water as solvent. The resulting polymeric building block has a poly(thioether urethane) backbone, with hydroxyl- and amino acid side groups; the connection of the amino acid to the backbone occurs by an amide bond. As proof of concept, a selected series of amino acids and derivatives of such is used: glycine, alanine, tyrosine, glutamic acid, ε-amino caproic acid (as a lysine surrogate), BOC-lysine-O-methyl ester, BOC-lysine, and the dipeptide carnosine. The resulting polymer building blocks with molecular weights of Mn = 1830–9590 g/mol are entirely based on both bio-based and biodegradable components. Exemplarily, using the lithium salts of glycine and lysine methyl ester, anionic and cationic polyelectrolyte building blocks are obtained. A mixture of the two polyelectrolyte solutions results in the formation of polyelectrolyte complexes (PECs). With decreasing concentration of the polyelectrolyte solutions, the radii of PECs decrease.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this manuscript, a biscyclic monomer with an epoxide and a thiolactone ring connected by a urethane bond is used for the synthesis of amino acid-functional polyelectrolytes. In a first step, lithium salts of amino acids react selectively with the thiolactone ring by ring-opening, formation of an amide bond, and a thiol group. In a second step and in the presence of a base a polymeric building block is formed by polyaddition of the thiolate to the epoxide ring. The reaction occurs at room temperature in water as solvent. The resulting polymeric building block has a poly(thioether urethane) backbone, with hydroxyl- and amino acid side groups; the connection of the amino acid to the backbone occurs by an amide bond. As proof of concept, a selected series of amino acids and derivatives of such is used: glycine, alanine, tyrosine, glutamic acid, ε-amino caproic acid (as a lysine surrogate), BOC-lysine-O-methyl ester, BOC-lysine, and the dipeptide carnosine. The resulting polymer building blocks with molecular weights of Mn = 1830–9590 g/mol are entirely based on both bio-based and biodegradable components. Exemplarily, using the lithium salts of glycine and lysine methyl ester, anionic and cationic polyelectrolyte building blocks are obtained. A mixture of the two polyelectrolyte solutions results in the formation of polyelectrolyte complexes (PECs). With decreasing concentration of the polyelectrolyte solutions, the radii of PECs decrease.
2016
6.
Mommer, Stefan; Truong, Khai-Nghi; Keul, Helmut; Moller, Martin
An epoxy thiolactone on stage: four component reactions, synthesis of poly(thioether urethane)s and the respective hydrogels Journal Article
In: Polymer Chemistry, vol. 7, pp. 2291-2298, 2016, ISSN: 1759-9954.
@article{RN787,
title = {An epoxy thiolactone on stage: four component reactions, synthesis of poly(thioether urethane)s and the respective hydrogels},
author = {Stefan Mommer and Khai-Nghi Truong and Helmut Keul and Martin Moller},
url = {http://dx.doi.org/10.1039/C6PY00231E},
doi = {10.1039/C6PY00231E},
issn = {1759-9954},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
journal = {Polymer Chemistry},
volume = {7},
pages = {2291-2298},
abstract = {The synthesis of an epoxy thiolactone is described. The reactivity of this epoxy thiolactone towards amines is evaluated and presented in a four component reaction. Upon ring opening of the thiolactone with an amine an AB-type epoxy thiol monomer is generated which in situ starts a thiol-epoxy polymerization. The polymerization mechanism and kinetics are investigated: the influence of different parameters such as solvent, substrate concentration, and catalyst on the reaction course is explored. Finally, concepts for the formation of reactive hydrogels are presented.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The synthesis of an epoxy thiolactone is described. The reactivity of this epoxy thiolactone towards amines is evaluated and presented in a four component reaction. Upon ring opening of the thiolactone with an amine an AB-type epoxy thiol monomer is generated which in situ starts a thiol-epoxy polymerization. The polymerization mechanism and kinetics are investigated: the influence of different parameters such as solvent, substrate concentration, and catalyst on the reaction course is explored. Finally, concepts for the formation of reactive hydrogels are presented.
2015
5.
Mommer, Stefan; Köhler, Jens; Keul, Helmut; Möller, Martin
Light-Controlled Radical Polymerization of Functional Methacrylates Prepared by Enzymatic Transacylation Journal Article
In: Macromolecular Chemistry and Physics, vol. 217, pp. 9-23, 2015, ISSN: 1521-3935.
@article{RN761,
title = {Light-Controlled Radical Polymerization of Functional Methacrylates Prepared by Enzymatic Transacylation},
author = {Stefan Mommer and Jens Köhler and Helmut Keul and Martin Möller},
url = {http://dx.doi.org/10.1002/macp.201500351},
doi = {10.1002/macp.201500351},
issn = {1521-3935},
year = {2015},
date = {2015-01-01},
urldate = {2015-01-01},
journal = {Macromolecular Chemistry and Physics},
volume = {217},
pages = {9-23},
abstract = {Well-defined homo and block copolymers are prepared with methyl methacrylate, pentyl methacrylate, 3-phenylpropyl methacrylate, and 6-thiobenzoylhexyl methacrylate using Ir(ppy)3 as a catalyst. It is shown that the advantages of the light-controlled radical polymerization can be exploited also for these special monomers as prepared by enzymatic transacylation without time-consuming labor-intensive removal of side products. Furthermore, it is shown that the polymerization is significantly affected even by small variations in the irradiation and therefore also by choice of the light source. In contrast to our recent report we therefore recommend removal of the heterogeneous supported enzyme by filtration before polymerization. Because of the sensitivity of the polymerization process to the irradiation, turbidity caused by the bead-supported enzyme can affect the reproducibility of the polymer preparation. Results obtained with methyl methacrylate as monomer could only be transferred to the above-mentioned functional monomers by proper choice of the light source. On the basis of kinetic investigations, the effect of the irradiation source, the catalyst concentration, and the alcohol residue on the methacrylate used are discussed. Finally, the optimized experimental conditions are applied for the preparation of different block copolymers. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Well-defined homo and block copolymers are prepared with methyl methacrylate, pentyl methacrylate, 3-phenylpropyl methacrylate, and 6-thiobenzoylhexyl methacrylate using Ir(ppy)3 as a catalyst. It is shown that the advantages of the light-controlled radical polymerization can be exploited also for these special monomers as prepared by enzymatic transacylation without time-consuming labor-intensive removal of side products. Furthermore, it is shown that the polymerization is significantly affected even by small variations in the irradiation and therefore also by choice of the light source. In contrast to our recent report we therefore recommend removal of the heterogeneous supported enzyme by filtration before polymerization. Because of the sensitivity of the polymerization process to the irradiation, turbidity caused by the bead-supported enzyme can affect the reproducibility of the polymer preparation. Results obtained with methyl methacrylate as monomer could only be transferred to the above-mentioned functional monomers by proper choice of the light source. On the basis of kinetic investigations, the effect of the irradiation source, the catalyst concentration, and the alcohol residue on the methacrylate used are discussed. Finally, the optimized experimental conditions are applied for the preparation of different block copolymers.
2014
4.
Mommer, Stefan; Keul, Helmut; Möller, Martin
Tailored Thiol-Functional Polyamides: Synthesis and Functionalization Journal Article
In: Macromolecular Rapid Communications, vol. 35, pp. 1986-1993, 2014, ISSN: 1521-3927.
@article{RN428,
title = {Tailored Thiol-Functional Polyamides: Synthesis and Functionalization},
author = {Stefan Mommer and Helmut Keul and Martin Möller},
url = {http://dx.doi.org/10.1002/marc.201400377},
doi = {10.1002/marc.201400377},
issn = {1521-3927},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
journal = {Macromolecular Rapid Communications},
volume = {35},
pages = {1986-1993},
abstract = {Well-defined homo and block copolymers are prepared with methyl methacrylate, pentyl methacrylate, 3-phenylpropyl methacrylate, and 6-thiobenzoylhexyl methacrylate using Ir(ppy)3 as a catalyst. It is shown that the advantages of the light-controlled radical polymerization can be exploited also for these special monomers as prepared by enzymatic transacylation without time-consuming labor-intensive removal of side products. Furthermore, it is shown that the polymerization is significantly affected even by small variations in the irradiation and therefore also by choice of the light source. In contrast to our recent report we therefore recommend removal of the heterogeneous supported enzyme by filtration before polymerization. Because of the sensitivity of the polymerization process to the irradiation, turbidity caused by the bead-supported enzyme can affect the reproducibility of the polymer preparation. Results obtained with methyl methacrylate as monomer could only be transferred to the above-mentioned functional monomers by proper choice of the light source. On the basis of kinetic investigations, the effect of the irradiation source, the catalyst concentration, and the alcohol residue on the methacrylate used are discussed. Finally, the optimized experimental conditions are applied for the preparation of different block copolymers. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Well-defined homo and block copolymers are prepared with methyl methacrylate, pentyl methacrylate, 3-phenylpropyl methacrylate, and 6-thiobenzoylhexyl methacrylate using Ir(ppy)3 as a catalyst. It is shown that the advantages of the light-controlled radical polymerization can be exploited also for these special monomers as prepared by enzymatic transacylation without time-consuming labor-intensive removal of side products. Furthermore, it is shown that the polymerization is significantly affected even by small variations in the irradiation and therefore also by choice of the light source. In contrast to our recent report we therefore recommend removal of the heterogeneous supported enzyme by filtration before polymerization. Because of the sensitivity of the polymerization process to the irradiation, turbidity caused by the bead-supported enzyme can affect the reproducibility of the polymer preparation. Results obtained with methyl methacrylate as monomer could only be transferred to the above-mentioned functional monomers by proper choice of the light source. On the basis of kinetic investigations, the effect of the irradiation source, the catalyst concentration, and the alcohol residue on the methacrylate used are discussed. Finally, the optimized experimental conditions are applied for the preparation of different block copolymers.
2013
3.
Mommer, Stefan; Lamberts, Kevin; Keul, Helmut; Moller, Martin
A novel multifunctional coupler: the concept of coupling and proof of principle Journal Article
In: Chemical Communications, vol. 49, no. 32, pp. 3288-3290, 2013, ISSN: 1359-7345.
@article{RN324,
title = {A novel multifunctional coupler: the concept of coupling and proof of principle},
author = {Stefan Mommer and Kevin Lamberts and Helmut Keul and Martin Moller},
url = {http://dx.doi.org/10.1039/C3CC40369F},
doi = {10.1039/C3CC40369F},
issn = {1359-7345},
year = {2013},
date = {2013-01-01},
urldate = {2013-01-01},
journal = {Chemical Communications},
volume = {49},
number = {32},
pages = {3288-3290},
abstract = {A multifunctional coupler with an ethylene carbonate- and a thiolactone ring was synthesized. As proof of principle the coupler was reacted with four low-molecular weight building blocks to form a multifunctional molecule. The reactivity/selectivity of the coupler towards amines, acrylates and acyl halides was evaluated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A multifunctional coupler with an ethylene carbonate- and a thiolactone ring was synthesized. As proof of principle the coupler was reacted with four low-molecular weight building blocks to form a multifunctional molecule. The reactivity/selectivity of the coupler towards amines, acrylates and acyl halides was evaluated.
2.
Burns, David J.; Mommer, Stefan; O’Brien, Peter; Taylor, Richard J. K.; Whitwood, Adrian C.; Hachisu, Shuji
Stereocontrolled Synthesis of the AB Rings of Samaderine C Journal Article
In: Organic Letters, vol. 15, no. 2, pp. 394-397, 2013, ISSN: 1523-7060.
@article{RN1925,
title = {Stereocontrolled Synthesis of the AB Rings of Samaderine C},
author = {David J. Burns and Stefan Mommer and Peter O’Brien and Richard J. K. Taylor and Adrian C. Whitwood and Shuji Hachisu},
url = {https://doi.org/10.1021/ol303385a},
doi = {10.1021/ol303385a},
issn = {1523-7060},
year = {2013},
date = {2013-01-01},
urldate = {2013-01-01},
journal = {Organic Letters},
volume = {15},
number = {2},
pages = {394-397},
abstract = {A concise synthesis of the AB rings of samaderine C (12 steps, 8 isolation steps, 7.8% overall yield), a quassinoid with antifeedant and insecticidal activity, is described. The development of the first general approach to the trans-1,2-diol A-ring motif in samaderine C and other quassinoids is a key feature. The trans-1,2-diol is crafted via stereoselective α-hydroxylation (of a silyl enol ether) and reduction, a strategy that has much potential for quassinoid synthesis.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A concise synthesis of the AB rings of samaderine C (12 steps, 8 isolation steps, 7.8% overall yield), a quassinoid with antifeedant and insecticidal activity, is described. The development of the first general approach to the trans-1,2-diol A-ring motif in samaderine C and other quassinoids is a key feature. The trans-1,2-diol is crafted via stereoselective α-hydroxylation (of a silyl enol ether) and reduction, a strategy that has much potential for quassinoid synthesis.
1.
Keul, Helmut; Mommer, Stefan; Möller, Martin
Poly(amide urethane)s with functional/reactive side groups based on a bis-cyclic bio-based monomer/coupling agent Journal Article
In: European Polymer Journal, vol. 49, no. 4, pp. 853-864, 2013, ISSN: 0014-3057.
@article{RN274,
title = {Poly(amide urethane)s with functional/reactive side groups based on a bis-cyclic bio-based monomer/coupling agent},
author = {Helmut Keul and Stefan Mommer and Martin Möller},
url = {http://www.sciencedirect.com/science/article/pii/S001430571200359X},
doi = {10.1016/j.eurpolymj.2012.10.024},
issn = {0014-3057},
year = {2013},
date = {2013-01-01},
urldate = {2013-01-01},
journal = {European Polymer Journal},
volume = {49},
number = {4},
pages = {853-864},
abstract = {Glycerol and d,l-homocysteine thiolactone – two bio-based building blocks – were used to prepare a bis-cyclic AA′ monomer (or coupler) with an ethylene carbonate and a thiolactone ring linked by an O-methyl urethane spacer. On reaction of this monomer with diamines at 70 °C poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups are produced in one step. Monodisperse diamines of low molecular weight (Mw), monodisperse amino telechelic poly(ethylene oxide) (MW = 897.10) and polydisperse amino telechelic polytetrahydrofuran (Mn = 1100) were used as amine building blocks. By reaction of the coupler with diamines at room temperature only the thiolactone ring is converted. Consequently, a bis(ethylene carbonate) bis(thiol) is obtained if one equivalent diamine is reacted with two equivalents of coupler. Reaction of this intermediate with a second diamine leads to poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups and alternating amine building blocks. Post-polymerization modification of thiol side groups leads to polymers with designed properties. The microstructure of the obtained polymers was proven by 1H NMR and Raman spectroscopy; the molecular weights were determined by size exclusion chromatography.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Glycerol and d,l-homocysteine thiolactone – two bio-based building blocks – were used to prepare a bis-cyclic AA′ monomer (or coupler) with an ethylene carbonate and a thiolactone ring linked by an O-methyl urethane spacer. On reaction of this monomer with diamines at 70 °C poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups are produced in one step. Monodisperse diamines of low molecular weight (Mw), monodisperse amino telechelic poly(ethylene oxide) (MW = 897.10) and polydisperse amino telechelic polytetrahydrofuran (Mn = 1100) were used as amine building blocks. By reaction of the coupler with diamines at room temperature only the thiolactone ring is converted. Consequently, a bis(ethylene carbonate) bis(thiol) is obtained if one equivalent diamine is reacted with two equivalents of coupler. Reaction of this intermediate with a second diamine leads to poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups and alternating amine building blocks. Post-polymerization modification of thiol side groups leads to polymers with designed properties. The microstructure of the obtained polymers was proven by 1H NMR and Raman spectroscopy; the molecular weights were determined by size exclusion chromatography.
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