Crosslinking Dynamics and Gelation Characteristics of Photo- and Thermally Polymerized Poly(Ethylene Glycol) Hydrogels

Abstract

The crosslinking behaviors and gelation features of poly(ethylene glycol) (PEG) hydrogels were scrutinized during the UV and thermal polymerizations of mixtures of poly(ethylene glycol) methacrylate (PEGMA, monomer) and poly(ethylene glycol) dimethacrylates (PEGDMAs, crosslinkers). The real-time crosslinking behavior of the PEG hydrogels was quantified as a function of the UV irradiation time and reaction temperature during the UV and thermal polymerization, respectively, using real-time FT-IR spectrometry and rotational rheometry. The gelation characteristics of UV- and thermally crosslinked hydrogels were compared through the analysis of the gel fraction, swelling ratio, surface hardness, and the loading and release of rhodamine-B. The gelation properties of the cured hydrogel films were suitably correlated with the real-time rheological properties and crosslinked network state of the PEG mixtures. The crosslinking and gelation properties of the cured hydrogels could be optimally tuned by not only the molecular weight of the crosslinker but also the UV or thermal polymerization conditions.

UV-VIS Curable PEG Hydrogels for Biomedical Applications with Multifunctionality

“…Figure 1 shows the UV-Vis spectra before and after crosslinking for the novel PIs. In general, for all new PEG-DA hydrogels, we find spectra shifted somewhat toward higher wavelengths compared to the pure PIs [ 24 , 25 ], while crosslinking tends to cause a small shift toward lower wavelengths, as already substantiated in the literature [ 26 ].…”

Volume Holographic Structuring of Special Hydrogel Films by Photochemical Crosslinking

“…Figure 6 shows the UV-Vis spectra before and after crosslinking for the novel PIs. In general, for all new PEG-DA hydrogels, we find the absorption band of the dye in the polymer matrix shifted somewhat toward higher wavelengths compared to the pure PIs [44,45], while crosslinking tends to cause a small shift toward lower wavelengths again, as already substantiated in the literature [46].…”

Colored electrolytes for electrochromic devices

“…For the other treated electrolytes, this peak is almost non existent and a polymerization with a high rate of conversion is deduced. Note that the C=O peak in the methacrylate group was slightly shifted toward a higher wavenumber, from 1716 to 1725 cm −1 , implying an increased carbonyl bond strength due to the loss of conjugation between the olefin and carbonyl groups during UV curing, as is already substantiated in the literature [37,38]. Considering the C=C peak deacrease and the C=O peak shift of the treated electrolytes, it can be concluded that the addition of pigments doesn't influence the polymerization conversion.…”