ACS polymers Au最新文献

Selective sensing and removal of toxic heavy metals from water are highly essential since their presence poses significant health and environmental hazards. Herein, we designed and synthesized a novel fluorescent nonconjugated organic polymer by strategically incorporating two key functional groups, namely, a dansyl fluorophore and dithiocarbamate (DTC). Different characterization techniques, including ¹H nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR), and fluorescence spectroscopy, were performed to understand its structure and material properties. The quantum yield of 4.72% and its solid-state fluorescence indicate that it has potential for various applications in several technological and scientific domains. In this study, we investigated a specific application involving the detection and elimination of heavy metals from water. Interestingly, the presence of dansyl and DTC moieties demonstrated remarkable selectivity toward Cu²⁺, Co²⁺, Ni²⁺, Fe³⁺, and Fe²⁺ sensing, displaying distinct color changes specific to each metal. Cu²⁺ resulted in a yellow color, Co²⁺ showed a green color, Ni²⁺ displayed a pale yellowish-green color, and Fe²⁺/Fe³⁺ exhibited a brown color. The LOD (limit of detection) for each metal was obtained in the nanomolar range by using a fluorescence spectrometer and the micromolar range from UV–visible spectra: 13.27 nM and 0.518 μM for Cu²⁺, 8.27 nM and 0.581 μM for Co²⁺, 14.36 nM and 0.140 μM for Ni²⁺, 14.95 nM and 0.174 μM for Fe²⁺, and 15.54 nM and 0.33 μM for Fe³⁺. Moreover, the DTC functionality on its backbone facilitates effective interaction with the aforementioned heavy metals, subsequently removing them from water (except Fe²⁺ and Fe³⁺), validating its dual functionality as both an indicator and a purifier for heavy metals in water. The polymer exhibited a maximum adsorption capacity of 192.30 mg/g for Cu²⁺, 159.74 mg/g for Co²⁺, and 181.81 mg/g for Ni²⁺. Furthermore, this approach exhibits versatility in crafting fluorescent polymers with adjustable attributes that are suitable for a wide range of applications.

The Covid-19 pandemic increased enormously the manufacturing and usage of face masks and other personal protective equipment (PPE), resulting in accumulation of plastic waste and, thus, causing universal environmental concerns. In addressing the issue of waste reduction and finding alternatives for fossil-based products, investigation of different biobased and biodegradable polymers plays a crucial role. This study examines the processability characteristics of three commonly used biobased polymers available in the market: biobased poly(lactic acid) (PLA), partly biobased and biodegradable poly(butylene succinate) (PBS), and biobased high-density poly(ethylene) (BioHDPE). The investigation combines substantial polymer analysis with subsequent processability trials in two different spunmelt processes, namely, meltblow (MB) and the Nanoval technology, aiming to reveal the differences and difficulties in the processing behavior and pointing out advantages and/or disadvantages of the respective polymer/technology combination. In general, the observed processability behavior and outcomes indicate that within the used processes PLA exhibits superior processability compared to PBS and BioHDPE. Both the meltblow and Nanoval processing of PLA demonstrated a consistent production of fibers and efficient uptake without any compromise on the throughput. In contrast, the processing of PBS using Nanoval required the utilization of significantly elevated temperatures, as indicated by a rheological study. Furthermore, the rheological evaluation revealed that the viscosity of BioHDPE was excessively elevated, rendering it unsuitable for effective processing by the Nanoval method. The microfibers in the PLA-based meltblown fabric had a higher surface area, explaining why the PLA fibers were able to function as a barrier and, thus, contribute to the mitigation of air permeability adjustable between 500 and 1000 l·s^–1·m^–2 and thus competitive or even superior to PP nonwovens of the same fiber diameter and base weight (1480 l·s^–1·m^–2). Overall, these results showed that PLA can be an alternative raw material for fossil-based nonwovens of PPE applying, especially, the meltblown technique.

In this article, we report a series of functionalized polyacetylene-type networks formed by chain-growth insertion coordination polymerization in high internal phase emulsions (HIPEs). All polymerized HIPEs (polyHIPEs) contain a hierarchically structured, 3D-interconnected porous framework consisting of a micro-, meso- and macropore system, resulting in exceptionally high specific surface areas (up to 1055 m²·g^–1) and total porosities of over 95%. The combination of π-conjugated and hierarchically porous structure in one material enabled the use of these polyacetylene polyHIPEs as adsorptive photocatalysts for the removal of chemical contaminants from water. All polyacetylene polyHIPEs demonstrated high efficiency in the adsorption of bisphenol A from water (up to 48%) and the subsequent photocatalytic degradation. Surprisingly, high adsorption capacity did not affect the photocatalytic efficiency (up to 58%). On the contrary, this dual function seems to be very promising, as some polyacetylene polyHIPEs almost completely removed bisphenol A from water (97%) through the adsorption-photooxidation mechanism. It also appears that the presence of polar functional side groups in the polyacetylene backbone improves the contact of the polyacetylene network with the aqueous bisphenol A solution, which can thus be more easily adsorbed and subsequently oxidized, compensating for the lower specific surface area of some networks, namely, 471 and 308 m²·g^–1 in the case of 3-ethynylphenol- and 3-ethynylaniline-based polyacetylene polyHIPEs, respectively.

This study outlines the microfluidic (MF) controlled self-assembly of polylactide (PLA)-based linear and graft copolymers. The PLA-based copolymers (PLA-Cs) were synthesized through a convenient one-pot/one-step ROP/RAFT technique. Three distinct vinyl monomers─triethylene glycol methacrylate (TEGMA), 2-hydroxypropyl methacrylate (HPMA), and N-(2-hydroxypropyl) methacrylamide (HPMAA) were employed to prepare various copolymers: linear thermoresponsive polylactide-b-poly(triethylene glycol methacrylate) (PLA-b-PTEGMA), graft pseudothermoresponsive poly[N-(2-hydroxypropyl)] methacrylate-g-polylactide (PHPMA-g-PLA), and graft amphiphilic poly[N-(2-hydroxypropyl)] methacrylamide-g-polylactide (PHPMAA-g-PLA). The MF technology was utilized for the controlled self-assembly of these PLA-based BCs in a solution, resulting in a range of nanoparticle (NP) morphologies. The thermoresponsive PLA-b-PTEGMA diblock copolymer formed thermodynamically stable micelles (Ms) through kinetically controlled assemblies. Similarly, employing MF channels led to the self-assembly of PHPMA-g-PLA, yielding polymersomes (PSs) with adjustable sizes under the same solution conditions. Conversely, the PHPMAA-g-PLA copolymer generated worm-like particles (Ws). The analysis of resulting nano-objects involves techniques such as transmission electron microscopy, dynamic light scattering investigations (DLS), and small-angle X-ray scattering (SAXS). More specifically, the thermoresponsive behavior of PLA-b-PTEGMA and PHPMA-g-PLA nano-objects is validated through variable-temperature DLS, TEM, and SAXS methods. Furthermore, the study explored the specific interactions between the formed Ms, PSs, and/or Ws with proteins in human blood plasma, utilizing isothermal titration calorimetry.

Nanoarchitectures such as micelles and vesicles that self-assemble via electrostatic interactions between their charged polymeric components have been widely used as material delivery platforms. In this work, ampholytic peptides with a sequence of alternating lysine and glutamic acid residues were designed and synthesized via chemoenzymatic polymerization. This alternating sequence was achieved by trypsin-catalyzed polymerization of a dipeptide monomer. Due to the electrostatic interaction between the anionic and cationic residues, the prepared ampholytic peptides spontaneously formed nanosized assemblies with a size of 100–200 nm in water. Modification with tetra(ethylene glycol) (TEG) at the N-terminus of these ampholytic alternating peptides resulted in the formation of stable nanosized assemblies, while peptides consisting of random sequences of lysine and glutamic acid formed large aggregates with deteriorated stability even with TEG modification. Morphological observations using a field-emission scanning electron microscope and an atomic force microscope revealed that the obtained assemblies were spherical and hollow, indicating the spontaneous formation of vesicles from the TEG-modified ampholytic alternating peptides. These vesicles were able to encapsulate a model fluorescent protein within their hollow structures without structural collapse causing loss of fluorescence, demonstrating the potential of these nanocarriers for use in material delivery systems.