Interactions between a biomedical thermoresponsive polymer and imidazolium-based ionic liquids: A comprehensive biophysical investigation

Tunable temperature-responsive photonic ionogels with dual signals output

Photonic ionogels with dual electrical and optical output have been intensively studied. However, tunable temperature-responsive photonic ionogel assembled by thermosensitive nanogels has not been studied yet. Herein, an innovative approach to fabricate photonic ionogels has been developed for smart wearable devices with tunable temperature sensitivity and structural color. Firstly, poly(isopropylacrylamide-r-phenylmaleanilic acid) P(NIPAm-r-NPMA) nanogels self-assemble into photonic crystals in 2-hydroxyethyl acrylate (HEA), water, and the ionic liquid of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate. And then robust photonic ionogels are developed through a polymerization of 2-hydroxyethyl acrylate crosslinked by poly(ethylene glycol) diacrylate (PEGDA). The incorporation of the ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, enhances the mechanical strength of photonic ionogels and tunes the temperature-sensitivity of the ionogels, making them adaptable to various environmental conditions. The findings demonstrate that these ionogels can serve dual functions in smart wearable devices, combining electrical and optical signal outputs due to the conductivity of the ionic liquid and structural color from the nanogel assembly. The resultant photonic ionogels exhibit exceptional substrate adhesion, mechanical stability, and fast resilience. More significantly, the nanogels within these ionogels serve as the building blocks of photonic crystals (PCs) endow with angle-independent coloration and enhance stretchability beyond 200 %, while the stretchability of the ionogles without the nanogels is only about 100 %. Our photonic ionogels with tunable temperature-sensitivity and dual outputs will open an avenue to the development of the innovative smart wearable devices.

Ionic Liquids Mediated Micellization of Pluronic Copolymers: Aggregation Behavior of Amphiphilic Triblock Copolymers

Understanding the micellization of amphiphilic triblock copolymers, especially Pluronics can play a persuasive role in engineering "smart" formulations for drug delivery applications. Their underlying self-assembly in the presence of designer solvents such as ionic liquids (ILs) provides combinatorial benefits of unique munificent properties of ILs and copolymers. The complex molecular interactions in the Pluronic copolymers/ILs mixed system influence the aggregation mechanism of copolymers depending on various aspects with no standardized factors to govern the structure-property relationship, which led to the practical applications. Here, we summarized recent progress in understanding the micellization process of IL-Pluronic mixed systems. Special emphasis was given to pure Pluronic systems (i.e., PEO-PPO-PEO) without any structural modifications, such as copolymerization with other functional groups, and ILs having cholinium and imidazolium groups. We expect that the correlation between existing/developing experimental and theoretical studies will provide the necessary basis and impetus for successful utilization in drug delivery applications.

Effect of Imidazolium Nitrate Ionic Liquids on Conformational Changes of Poly(N-vinylcaprolactam)

Detailed information about molecular interactions and conformational changes of polymeric components in the presence of ionic liquids (ILs) is essential for designing novel polymeric ionic liquid-based biomaterials. In biomaterials science and technology, thermoresponsive polymers (TRPs) are widely viewed as potential candidates for the fabrication of biorelated medical devices. Here, we synthesized thermoresponsive poly(N-vinyl-caprolactam) (PVCL) polymer and investigated the effects of imidazolium-based ILs (1-ethyl-3-methyl imidazolium nitrate and 1-butyl-3-methylimidazolium nitrate) with common anion and different cations on the phase transition behavior of PVCL aqueous solution. The impact of ILs on the phase transition behavior of PVCL was monitored by using UV-visible absorption spectra, steady-state fluorescence spectroscopy, thermal fluorescence spectroscopy, and temperature dependent dynamic light scattering. Results showed significant changes in the absorbance, molecular interactions, agglomeration, and coil to globule transition behaviors of PVCL in the presence of two ILs. PVCL aqueous solution showed significant conformational changes after the addition of ILs.