Recent progress in the development of highly active dyeing photoinitiators based on 1,3-bis(p-substituted phenylamino)squaraines for radical polymerization of acrylates

Abstract

The photopolymerization is a very popular technique used in the production of various polymeric materials. The key role in the light induced polymerization processes plays a photoinitiator. One of the...

Recent advances on visible light bodipys and related difluoroborane structures-based photoinitiating systems

“…[344] From the absorption viewpoint, the absorption range of 2phenacylbenzoxazole difluoroboranes is comparable to that of boranils, with absorption maxima ranging between 349 nm for PBX-5 up to 415 nm for PBX-1 comprising the most electron donating group of the series (See Table 7 and Figure 26). Comparison with the reference camphorquinone/N-phenylglycine system [88,[345][346][347] revealed the different PBX/Pyr systems to furnish slower polymerization rates.…”

High potential of new dyeing photoinitiators for fast curing of (meth)acrylate compositions under low intensity UV–Vis light

“…These organic dyes are promising candidates as sensitizers for highly efficient photoinitiating systems for radical and cationic polymerization due to their excellent photochemical and photophysical properties. 43,44 The typical features of squaraines are intense absorption and strong emission bands from the visible to the near infrared region, high extinction coefficients, high values of fluorescence quantum yield, good photoconductivity, and moderate photo and thermal stability. [45][46][47][48] These unique properties make them useful for applications in bioimaging, photodynamic therapy (PDT), nonlinear optics, photovoltaic devices, ion sensing, and sensitizers in photopolymerization reactions.…”

“…Next, 1,3-bis( p-substituted phenylamino)squaraines, 53 aniline-based squarylium dyes 54,55 and difluoroborate complexes of squaraine dyes 57 bonded via the imine group with a squaric acid ring were studied and described in the literature. 3,43,56,[58][59][60][61][62] In the present paper, the photosensitizers are based on benzothiazole derivatives connected via an imino group to a squaric acid moiety, which essentially distinguishes the previously described chromophores. The use of this type of photoinitiator has not been described in the literature and allows us to deepen our knowledge about the possibility of using new squaraines in processes involving light.…”

Diethoxycarbonyl-BODIPYs as heavy-atom-free photosensitizers for holographic recording in cellulose acetate photopolymer

“…which act as co-initiators. 4 A photosensitizer component undergoes intersystem crossing (ISC) and forms long-living triplet excited states which are able to initiate chemical transformation leading to free radical formation and thus cause polymerization. ISC is a spin-forbidden process and so chemical structures of potential PSs must be rationally designed to enhance triplet state yields ( Φ T ) and lifetimes ( τ T ).…”