Photocleavable epoxy based materials

Radl, Simone; Kreimer, M. L.; Manhart, Jakob; Grießer, Thomas; Möser, Andreas; Pinter, Gerald; Kalinka, Gerhard; Kern, Wolfgang; Schlögl, Sandra

doi:10.1016/j.polymer.2015.05.055

Cited by 21 publications

(20 citation statements)

References 49 publications

(37 reference statements)

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“…(2‐Nitro‐1,4‐phenylene) bis(methylene) bis(2‐(oxiran‐2‐yl)acetate) (epoxy‐ NBE ) as photosensitive monomer was synthesized as previously reported in ref. . Succinic anhydride terminated polydimethylsiloxane with a molecular mass of 600–800 g mol −1 and a viscosity of 75–100 cSt was supplied by abcr (Karlsruhe, Germany).…”

Section: Methodsmentioning

confidence: 99%

“…The reaction benefits from high versatility. Recently, we have highlighted the design of photoresponsive epoxy‐based networks that undergo controlled network degradation upon UV exposure . The photosensitive links enabled a spatially controlled degradation of the covalent polymer network upon UV exposure and a switch both in the solubility properties and in the thermomechanical performance.…”

Section: Introductionmentioning

confidence: 99%

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Dual‐Responsive Polydimethylsiloxane Networks

Giebler

Radl

Ast

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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Exploiting the salient features of o‐nitrobenzyl chemistry, this work aims at the preparation of polydimethylsiloxane networks that undergo well‐defined bond cleavage in response to either UV light or different pH values as external trigger. Polydimethylsiloxane (PDMS) oligomers with terminal anhydride groups are thermally crosslinked in the presence of a bi‐functional epoxy monomer containing a photolabile o‐nitrobenzyl ester (o‐NBE) group. The susceptibility of the ester groups toward hydrolytic cleavage reactions is used for a pH‐triggered network degradation. Sol–gel analysis confirms that the degradation time can be easily controlled by the base concentration over different time scales varying between hours and weeks. Along with classical ester hydrolysis, photoinduced degradation of the elastomeric networks is carried out by photoisomerization and cleavage of the o‐NBE links upon exposure with UV light. Positive‐tone patterns with a structure size of 100 μm are obtained by photolithographic techniques confirming the spatial control of solubility properties. However, by increasing the exposure dose, recrosslinking of the networks is observed due to side reactions of the primary photocleavage products. As the reformed crosslinks are less sensitive to ester hydrolysis, the side reactions are employed to inscribe negative‐tone microstructures in the PDMS network. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2319–2329

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dual‐Responsive Polydimethylsiloxane Networks

Giebler

Radl

Ast

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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“…At prolonged UV exposure, a re‐crosslinking of the cleaved polymer chains is observed through secondary reactions (e.g., formation of azobenzene groups by dimerization of nitroso‐benzaldehyde moieties) that leads to an increase in the gel content. [ 16–21 ]…”

Section: Figurementioning

confidence: 99%

“…[ 15 ] In previous studies, we explored the possibility to introduce o ‐NBE moieties in a wide range of different networks such as epoxy and methacrylic ones as well as thiol‐ene, thiol‐epoxy and thiol‐yne polymer networks fabricated by click chemistry. [ 16–20 ] In this context, thiol‐ene networks containing o ‐NBE moieties were used as positive/negative tone photoresist with good resolution. [ 21 ] In addition to the use of o ‐NBE for producing photoresists, we also showed the possibility to modify surface properties of the network through UV‐induced photocleavage, by exploiting the formation of polar species such as carboxylic acids.…”

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confidence: 99%

“…[ 22 ] Here we also evidence that the use of a laser source for activating the cleavage reaction is of particular interest since it allows not only high spatial control but also enables dry development (i.e., removal of cleaved molecules without the use of a solvent) while typically solvents are required to remove the soluble species formed in the exposed areas. [ 15–20,23,24 ]…”

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confidence: 99%

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Laser‐Triggered Writing and Biofunctionalization of Thiol‐Ene Networks

Romano

Angelini

Rossegger

et al. 2020

Macromol. Rapid Commun.

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The light responsivity of ortho‐nitrobenzyl esters (o‐NBE) is exploited to inscribe µ‐scale 2.5D patterns in thiol‐ene networks by direct laser writing. For this purpose, a multifunctional thiol and a photosensitive alkene with an o‐NBE chromophore are cured upon visible light exposure without inducing a premature photocleavage of the o‐NBE links. Once the network is formed, a laser beam source with a wavelength of 375 nm is used for selectively inducing the photocleavage reaction of the o‐NBE groups. Positive tone patterns are directly inscribed onto the sample surface without the requirement of a subsequent development step (removing soluble species in an appropriate organic solvent). Along with the realization of dry‐developable micropatterns, the chemical surface composition of the exposed areas can be conveniently adjusted since different domains with a tailored content of carboxylic groups are obtained simply by modulating the laser energy dose. In a following step, those are activated and exploited as anchor points for attaching an Alexa‐546 conjugated Protein A. Thus, the laser writable thiol‐ene networks do not only provide a convenient method for the fabrication of positive tone patterns but also open future prospectives for a wide range of biosensing applications.

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Photopatternable and Rewritable Epoxy‐Anhydride Vitrimers

Giebler

Alabiso

Wieser

et al. 2020

Macromol. Rapid Commun.

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The present work highlights a new approach to write, erase, and rewrite micropatterns into the same region of covalent adaptable polymer networks. Thermal curing of an epoxy‐terminated o‐nitrobenzyl ester (o‐NBE) derivative with hexahydrophthalic anhydride in the presence of 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene yields a dynamic covalent network, whose solubility is locally controlled by irradiation with ultraviolet (UV) light. The photolysis of the o‐NBE chromophores enables a well‐defined cleavage of the epoxy‐anhydride network, and the formation of soluble photolysis products is confirmed by sol‐gel analysis. The photo‐induced change in solubility is exploited to inscribe micropatterns by photolithographic techniques and after development in an organic solvent positive tone structures with a feature size of 20 µm are obtained. Due to the thermo‐activated exchange reactions of the hydroxyl ester links and the related macroscopic reflow, the polymer patterns are fully erased at temperatures well above the topological freezing transition of the vitrimer network. The regenerated film has a smooth surface topology and can be reused to inscribe new micropatterns via mask lithography.

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Photocleavable epoxy based materials

Cited by 21 publications

References 49 publications

Dual‐Responsive Polydimethylsiloxane Networks

Dual‐Responsive Polydimethylsiloxane Networks

Laser‐Triggered Writing and Biofunctionalization of Thiol‐Ene Networks

Photopatternable and Rewritable Epoxy‐Anhydride Vitrimers

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