Studying the polymerization initiation efficiency of acetophenone-type initiators via PLP-ESI-MS and femtosecond spectroscopy

Abstract

The initiation efficiency and the excited state dynamics of the three triplet radical photoinitiators MMMP (2-methyl-4 0 -(methylthio)-2-morpholinopropiophenone), benzoin (2-hydroxy-1,2-diphenylethanone, Bz), and 4-methyl benzoin (2-hydroxy-2-phenyl-1-(p-tolyl) ethanone, 4MB) are investigated via a trifold combination of pulsed laser polymerization and subsequent electrospray ionization mass spectrometry

Photophysical Properties of Benzoylgermane and para‐Substituted Derivatives: Substituent Effects on Electronic Transitions

“…For example, the use of a radical trapping reagent or EPR investigations could help to put the theoretical results on a more sound footing. Additionally, the qualitative statements about probabilities of bond fissions made in this study are currently improved toward quantification by combining pulsed laser polymerization with subsequent electrospray ionization mass spectrometry and femtosecond absorption spectroscopy . Regarding other benzoylgermane derivatives, compounds with meta ‐subsituents could be interesting objects for future theoretical and experimental research.…”

“…Additionally,t he qualitative statements about probabilities of bond fissions made in this study are currently improved toward quantification by combining pulsed laser polymerizationw ith subsequent electrospray ionization mass spectrometry and femtosecond absorption spectroscopy. [15,16,43] Regarding other benzoylgermane derivatives, compoundsw ith meta-subsituents could be interesting objectsf or future theoretical and experimental research. Assuming that the proposed application of organic chemistry concepts for excited states is suitable, ac yano substituent in meta position should lead to excited states that are less stabilized compared to the excited states of para-substituted compounds.…”

“…It is thus desirable to gain a more comprehensive understanding of the underlying mechanisms, especially the influence of substitution on excited‐state properties. Recently, such studies were performed for benzoin‐type photoinitiators by combining pulsed‐laser polymerization with subsequent electrospray ionization and mass spectrometry (PLP‐ESI‐MS), femtosecond absorption spectroscopy and TDDFT calculations …”

“…Recently,s uch studies were performed for benzoin-type photoinitiators by combining pulsedlaser polymerizationw ith subsequent electrospray ionization and mass spectrometry (PLP-ESI-MS), femtosecond absorption spectroscopy and TDDFT calculations. [15,16] In the present study,aselection of basic substitution patterns on benzoyl(trimethyl)germane was investigated using time-dependentdensity-functional theory (TDDFT) to explore the influence on the stabilitya nd on the relative order of the lowest excited electronic states. The theoretical results are in agreement with absorption and fluorescencem easurements.…”

Preparation of Single Chain Nanoparticles via Photoinduced Double Collapse Process

“…Photoinduced radical polymerization technique has been used in extensive applications such as curing of polymeric coatings, polymers with controlled molecular weight, linear and branched copolymers, and preparation of nanoparticles. Free radical photoinitiators are divided into two particular subgroups: i) Type I that is subjected to direct cleavage and widely used in various photoapplications and ii) Type II, which has longer wavelength absorption characteristics compared to Type I photoinitiators . Benzophenone is a conventional Type II initiator and used in various UV‐curing applications such as microelectronics, production of 3D objects, coatings, etc .…”