Impact of photoinitiators on the photopolymerization and the optical properties of inorganic–organic hybrid polymers

Abstract

Sol-gel synthesis allows one to produce inorganic–organic hybrid polymer materials which can be functionalized in order to tailor their physical and chemical properties. Besides, the resulting material properties are significantly influenced by further technological processing of the materials in thin film technology, i.e., the photochemical and thermal curing of the materials. In order to investigate the relationship between technological processing and material properties, a model system containing methacrylic groups as organically polymerizable units is chosen. The degree of conversion of the C=C double bond of the methacrylic group in dependence of the ultraviolet (UV) initiator concentration upon processing is characterized using Fourier-transform infrared spectroscopy. The data are correlated to measurements of the refractive indices at selected wavelengths.

Materials and technologies for fabrication of three-dimensional microstructures with sub-100 nm feature sizes by two-photon polymerization

“…[19][20][21] Furthermore, they exhibit excellent optical properties and biocompatibility, thus being a perfect material for micro-optical and biomedical applications. [22][23][24][25][26] For synthesis, alcoxysilane-precursors undergo hydrolysis and polycondensation reactions resulting in an organically modified inorganic-oxidic network ([Si-O] n ). This liquid resin can then be crosslinked photochemically and/or thermically resulting in solidified structures.…”

“…K can be calculated, 24 where A denotes the area of the respective peaks of the polymerized structure and A 0 is the liquid ORMOCER V R resin. Due to the overlapping of several peaks from initiator and ORMOCER V R in the spectral region of interest, a deconvolution of peaks has been applied using the commercial software Omnic from Thermo Scientific.…”

Degree of conversion versus the depth of polymerization of an organically modified ceramic dental restoration composite by fourier transform infrared spectroscopy

“…[13][14][15] Although ormocers are very promising, few investigations have confirmed the potential of ormocers as biomaterials or low-contraction materials applied to teeth restoration. Kim and coworkers 16,17 studied the degree of conversion of an ormocer by Fourier transform infrared (FTIR) for optical applications as a photonic material and therefore in the absence of inorganic fillers. Additionally, the material was employed as a thin film, and this suggested no dependence on the film thickness or depth of polymerization.…”

Two-Photon Polymerization of Inorganic-Organic Hybrid Polymers as Scalable Technology Using Ultra-Short Laser Pulses

“…Beside other findings, it was observed that the dependency of the voxel sizes on the initiator concentration is not linear. From investigations on the cross-linking behavior and the resulting refractive indices in dependence of the UV initiator concentrations which were carried out by one-photon processes (classical UV exposure), it was concluded that different initiator concentrations lead to different inorganic-organic hybrid networks in the final layer (Houbertz et al, 2004;Fodermeyer, 2009;Landgraf, 2010). Finally, the extraordinary performance of Ini3 should be underlined by the fact that voxel sizes comparable to the ones fabricated using Ini1 and Ini2 in a given ORMOCER ® material system were achieved with an about 200 times lower initial initiator concentration of Ini3 than of Ini1 or Ini2.…”

“…As internal reference, the C=C bond of the diphenylsilane precursor at 1569 cm -1 was used. The calculation of the degree of cross-linking was performed as reported in (Houbertz et al, 2004), and the first result is shown in Figure 12 (b). Analogously to the results from ORMOCER ® layers which were prepared by conventional UV lithography, the degree of cross-linking increases continuously until saturation for the given process conditions.…”