Photoinitiation mechanisms and photogelation kinetics of blue light induced polymerization of acrylamide with bicomponent photoinitiators

Abstract

Blue light induced free radical photopolymerization of acrylamide (AM) was studied using five bicomponent photoinitiators, camphorquinon, riboflavin-5 0phosphate sodium, curcumin, eosin Y, and Ru(bpy) 3 Cl 2 (Ru(II)) as photosensitizer, and diphenyliodonium hexafluorophosphate or potassium persulfate as electron acceptor. Fluorescence and UV-vis spectroscopies were used in combination with molecular orbital computations to characterize the photochemical behaviors of the five bicomponent photoinitiators, explore the possible electron transfer pathways of the photoinitiation processes, and quantify photopolymerization efficiencies. Real-time photogelation behavior of poly(AM) was monitored by Photo-differential scanning calorimetry and photo-rheometry. Photogelation kinetic parameters, including dG 0 (storage modulus)/dt, dG 00 (loss modulus)/dt, time delay of gelation (t d), and duration of gelation (Δt gel), were derived from photorheological data analyses and used to identify the best bicomponent photoinitiator candidate for rapid fabrication of blue light induced photopolymerizable hydrogels for biomedical applications.

New long-wavelength D–π-A–π-D chalcone photoinitiator for visible light polymerization with photobleaching and biocompatibility properties

“…[7][8][9][10] Therefore, in recent years, more and more attention has been paid to lower energy and soft visible irradiation sources such as LEDs, which can not only avoid safety problems, but also prevent deformation of materials at lower operating temperatures. [11][12][13][14] At present, the maximum absorption wavelength of free radical initiators on the market, such as photoinitiator 1173 and benzophenone, is below 365 nm, but the wavelength of LED light sources widely used in the industrial field is above 365 nm. Thus, this mismatch between the LED wavelength and the initiator absorption wavelength means that there is low initiation efficiency or that the LEDs cannot be used.…”

“…7–10 Therefore, in recent years, more and more attention has been paid to lower energy and soft visible irradiation sources such as LEDs, which can not only avoid safety problems, but also prevent deformation of materials at lower operating temperatures. 11–14…”

Synthesis and properties of acyldiphenylphosphine oxides photoinitiators carrying triphenylamine or pyrene group for free radical photopolymerization

“…Light‐curing technology has been widely used in inks, coatings, pressure‐sensitive adhesives, food packaging, dental resins, and biological materials fields due to energy saving, high efficiency, and almost no volatile organic compounds 1–10 . Typical light sources are medium and high‐pressure mercury lamps, which possesses some disadvantages including high energy consumption and environmental pollution, they would be replaced by ultraviolet‐light emitting diode (UV‐LED) 11–14 . However, due to the narrow ultraviolet spectrum of UV‐LED, including 365, 375, 385, 395, and 405 nm, UV‐LED curing can only be concentrated in a relatively narrow range of the ultraviolet spectrum.…”

“…[1][2][3][4][5][6][7][8][9][10] Typical light sources are medium and high-pressure mercury lamps, which possesses some disadvantages including high energy consumption and environmental pollution, they would be replaced by ultraviolet-light emitting diode (UV-LED). [11][12][13][14] However, due to the narrow ultraviolet spectrum of UV-LED, including 365, 375, 385, 395, and 405 nm, UV-LED curing can only be concentrated in a relatively narrow range of the ultraviolet spectrum. The emission bandwidth of each wavelength light source is about 10 nm.…”

Zeolite‐Reinforced Interpenetrating Polymer Network Initiated by Chalcone Based Photoinitiating System and Their Application in 3D/4D Printing

“…[25] In recent years, lots of extensive works have been published, which are devoted to develop new, efficient and highperformance PISs with good photoinitiation ability under the irradiation from near UV to visible or even NIR region. [19,[26][27][28][29][30][31][32][33] Among all photoinitiators, natural photoinitiators are candidate of choice for the manufacture of biocompatible polymer materials. [27] Chalcone is a class of natural dyes belonging to the flavonoids and exhibiting a low toxicity.…”