Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels

Abstract

Abstract:In this study, varying amounts of NIPAAm and an ionic liquid (IL), namely 1-vinyl-3-isopropylimidazolium bromide ([ViPrIm] + [Br] − ), have been used to synthesize hybrid hydrogels by radical emulsion polymerization. Amounts of 70/30%, 50/50%, 30/70%, 15/85% and 5/95% (wt/wt) of PIL/pNIPAAm were used to produce hybrid hydrogels as well as the parental hydrogels. The adhesive strength was investigated and evaluated for mechanical characterization. Thermal properties of resulting hydrogels have been investigated using differential scanning calorimetry (DSC) in a default heating temperature range (heating rate 10 K min −1 ). The presence of poly ionic liquids (PIL) in the polymer matrix leads to a moved LCST (lower critical solution temperature) to a higher temperature range for certain hybrid hydrogels PIL/pNIPAAm. While pNIPAAm exhibits an LCST at 33.9 ± 0.3°C, PIL/pNIPAAm 5/95% and PIL/pNIPAAm 15/85% were found to have LCSTs at 37.6 ± 0.9°C and 52 ± 2°C, respectively. This could be used for controlled drug release that goes along with increasing body temperature in response to an implantation caused infection.

Promising biocompatible hydrogels of crosslinked polyelectrolytes for biomedical applications

“…TEMED is used with APS to catalyze the polymerization and was added subsequently. Defined masses were mixed and dissolved in distilled water as described in detail in [10]. Subsequently, the HHGs (1 g) were swollen in deionised water (10 mL), whereby the medium was changed three times within 72 h.…”

“…Strong effects on volumetric changes and mechanical properties as well as drug release with these hybrid hydrogels (HHG) were already observed [10].…”

Rheological analysis of hybrid hydrogels during polymerization processes

“…Tetramethylethylenediamine (TEMED) is used with ammonium persulfate (APS) to catalyze the polymerization and was added subsequently. Defined masses were mixed and dissolved in distilled water as described in detail in [7]. The amount of TEMED was further doubled, but no significant effect on gelation was observed.…”

“…We previously reported an hybrid hydrogel system prepared from an ionic liquid ( [7]. Herein strong effects on volumetric changes and mechanical properties as well as thermoresponsive drug release were observed.…”

Reconstruction of biological functions: novel implant concepts for cardiovascular, ophthal-mologic and otolaryngologic applications

“…New structural scaffold designs, polymeric material formulations, magnesium alloys and process technologies are being investigated in order to overcome limitations of existing devices [2][3][4][5]. Furthermore, scaffold coatings with responsive drug release shall allow for an adaptive implant/tissue interaction in order to improve clinical outcome [6,7].…”