Macromolecular Chemistry and Physics最新文献

The effect of sodium iodide on the adsorption of a poly(ionic liquid)—poly(1-ethyl-3-vinylimidazolium bromide) (PVIm-Et)—onto conductive (gold and graphite/graphite-based) supports is examined by means of atomic force microscopy and flow-through quartz crystal microbalance with dissipation monitoring. The presence of sodium iodide is shown to decisively control the modification of the conductive surfaces by PVIm-Et, which remarkably enhances with the increasing salt concentration upon adsorption of the polymer. A subsequent binding of an enzyme—glucose oxidase (GOx)—by the PVIm-Et film is further examined by means of flow-through quartz crystal microbalance with dissipation monitoring. The amount of bound enzyme is found to correlate well with the efficiency of modification of the conductive surfaces by the polymer. To exemplify the application potential of the polymer-enzyme films, an electrochemical (amperometric) biosensor for quantification of β-D-glucose is constructed, wherein PVIm-Et is adsorbed in the presence of NaI (60 mM NaI) on a mediator (MnO₂)-modified graphite-based screen-printed electrode (SPE). The prepared SPE/MnO₂/PVIm-Et/GOx biosensor constructs exhibit remarkable analytical performance (a high sensitivity, a low limit of detection, and a broad linear range), demonstrating furthermore excellent stable enzymatic responses over manifold repeated measurements.

Isopropenyl 4-[bis(4-methylphenyl)amino]phenyl ketone (IMAPK) (1-[4-(di-p-tolylamino)phenyl)-2-methylprop-2-en-1-one], a vinyl ketone monomer bearing a triphenylamine moiety in the side chain, was copolymerized with methyl methacrylate (MMA) by a free radical method. While the vinyl ketone is known to show rather low reactivity in radical polymerization, the copolymerization reactions afforded polymers at higher monomer conversions. Photophysical and electrochemical properties of the copolymers were compared with those of t-butyl 4-[bis(4-methylphenyl)amino]phenyl ketone (BMAPK) (1-[bis(4-methylphenyl)amino]phenyl-2,2-dimethylpropan-1-one) as a model compound of IMAPK unit. The polymers and the model compound exhibit distinctive absorption and emission properties and oxidation potentials. Especially, the copolymer with a unit ratio of [IMAPK]/[MMA] = 1/7 showed as high as about 1.5 times higher emission efficiency than BMAPK.

Unlike dense bulk materials, the hollow structure of foam materials brings additional functionality and applications. Benefiting from the excellent biocompatibility of polyurethane, polyurethane foams have found numerous applications in the biomedical field. In terms of mechanical properties, beyond the selection of molecular structure, the performance of polyurethane foams can be effectively regulated by the pore structure. Functionally, in addition to achieving in vivo degradation, shape memory, and mechanical support like bulk polyurethane, the hollow pore structure enables critical capabilities such as exudate absorption and drug loading. Moreover, when used as a scaffold, the hollow structure is conducive to cell proliferation, growth, and migration, thereby facilitating tissue growth and repair. However, given the toxicity concerns associated with traditional isocyanates, non-isocyanate polyurethane foams (NIPUFs) are emerging as a crucial direction for the next generation of safer biomaterials. This review mainly summarizes the recent developments of thermoplastic polyurethane foams in the fields of dressings, scaffolds, embolization, and drug delivery. Significantly, it highlights the unique biomedical advantages of NIPUFs, outlining their preparation methods and preliminary applications as a promising alternative to conventional polyurethanes, with potential benefits in terms of improved sustainability and reduced carbon footprint.

In free radical ring-opening copolymerization of cyclic ketene acetals (CKA) with vinyl monomers, a major challenge is the often-low reactivity of CKAs and thus insufficient ester incorporation and homogeneity. Most workarounds, like semibatch copolymerization, require a considerable change in the system. In this work, we report a method to improve ester incorporation into the backbone and homogeneity of the polymer by using a batch copolymerization in 1,4-dioxane above solvent boiling point. The monomer system of 2-methylene-4-phenyl-1,3-dioxolane (MPDL) and syringyl methacrylate (SM) showed improved copolymerization parameters (r_MPDL = 0.032 and r_SM = 2.464) compared to the polymers obtained at 70°C in anisole. Basic hydrolysis with potassium hydroxide (KOH) in tetrahydrofuran (THF)/methanol (MeOH) was conducted to study structural homogeneity and was compared with semibatch experiments.