Photomediated post-fabrication modification of azlactone-functionalized gels for the development of hydrogel actuators

We report an approach for the photomediated post-fabrication modification of reactive, azlactone-containing gels using light-initiated deprotection of amines caged with 2-(nitrophenyl)propyloxycarbonyl (NPPOC). Photomediated modification of these gels can be used to generate a gradient in chemical functionality. When functionalized with tertiary amine groups, these gradient gels exhibit rapid and reversible shape deformations in response to changes in pH.

Fibrous Materials Based on Polymeric Salicyl Active Esters as Efficient Adsorbents for Selective Removal of Anionic Dye

To increase the performance efficiency and decrease the costs for organic dye wastewater purification, two fibrous adsorbents based on polymeric salicyl active esters were developed by means of a simple two-step approach. For the first time, salicyl-based active ester polymers were electrospun into fibrous membranes and subsequently postmodified with the desired functional groups under simple and mild reaction conditions. The morphology of the produced fibrous adsorbents was characterized by scanning electron microscopy (SEM), the surface properties were analyzed by nitrogen adsorption/desorption isotherms and contact angle measurements, and the completeness of the postmodification process was determined by Fourier transform infrared (FTIR) and elemental analyses. The adsorbents were further tested for their adsorption and selectivity performance of different organic dyes as well as for their recyclability. To explore the adsorption mechanism, four kinetic models and three isotherm models were used to analyze the adsorption data. The results indicated that the fibrous adsorbents showed an extremely high adsorption capacity for the anionic dye methyl blue. The fibrous adsorbents were also able to selectively adsorb anionic dyes from a mixture of anionic and cationic dyes, and they could be recycled at least 10 times. The simple and cost-efficient development process of these fibrous adsorbents and their excellent performance make them promising materials for further research and application in the area of water treatment.

A versatile synthetic platform for amphiphilic nanogels with tunable hydrophobicity

Functionalization of reactive precursor particles allows the preparation of amphiphilic nanogel libraries with tunable network hydrophobicity and comparable colloidal features.

UV-triggered shape-controllable PP fabric

A light-driven polypropylene (PP) fabric as an actuator was fabricated in which a light-responsive polymeric film acts as an active layer and a PP fabric acts as a passive layer.

pH-Regulated Controlled Swelling and Sustained Release from the Core Functionalized Amphiphilic Block Copolymer Micelle

pH-responsive amphiphilic block copolymers based on poly(ethylene glycol)monomethyl ether-b-poly(methyl methacrylate-co-methacrylamidepropanoic acid) (PEO-b-PMMA-co-PMAPA) with different MMA/MAPA ratios were synthesized from respective amine-reactive prepolymers based on poly(ethylene glycol)monomethyl ether-b-poly(methyl methacrylate-co-methacryloxysuccinimide) (PEO-b-PMMA-co-PMASI) in such a way that the pH-responsive carboxylic acid groups were randomly distributed in the hydrophobic (PMMA) block. In aqueous medium, they formed micellar aggregates. Control experiments showed stability and critical aggregation concentration and dye encapsulation properties were better for carboxylic acid functionalized micelles at acidic pH compared to a structurally similar block copolymer micelle that lacked any carboxylic acid group. This was attributed to H-bonding among the carboxylic acid groups. In basic pH upon deprotonation, controlled swelling of the aggregates was observed due to repulsion among the negatively charged carboxylate groups. The extent of swelling/deswelling was well controlled by simply changing the percentage of the pH-responsive units in the hydrophobic block and could be probed quantitatively by pH-dependent dynamic light scattering (DLS) and fluorescence resonance energy transfer (FRET) studies. The aggregates were able to encapsulate a hydrophobic guest such as pyrene at the interior of the micelle, and sustained release of this hydrophobic probe was achieved selectively at basic pH due to swelling of the micelles instead of complete disassembly that generally leads to burst release.