Fire warning materials always play an important role in safeguarding people’s lives and property. In general, existing approaches to realize supersensitive fire warning responses are typically focused on how to reduce response times. However, most strategies to effectively achieve fire warning require a high trigger temperature of over 180 °C that is unsuitable for fire warning of materials with a low flash point. Herein, a liquid metal-based shape memory material (LM-SMM) is fabricated by integrating liquid metal (LM), polydimethylsiloxane (PDMS), and polyurethane foam. The phase transition function of the LM contributes to better shape fixation properties. Meanwhile, the flexibility of PDMS assures good shape recovery performance. In particular, the LM-SMM still owns favorable electrical conductivity that could facilitate its application in advanced electronics. The combination of switchable structure and excellent electrical conductivity makes this LM-SMM appropriate for an ultrasensitive fire warning response. With the help of such performance, the LM-SMM can achieve the lowest fire-warning response temperature in a fast response time, which displays promising application in the safe storage of flammable materials. More importantly, this work could not only achieve the fabrication of highly conductive LM-SMM but also expand applications, thus providing possibilities for the next-generation supersensitive fire-warning response materials.

Developing broad-spectrum antifungal drugs represents a pressing need for reducing the global burden of fungal infections. We took advantage of the conformational stability effect to develop a high-avidity polymeric iron chelator, 2,3-dihydroxybenzoic acid-conjugated poly(l-lysine hydrochloride) (PLL-DHBA), which exhibited a stronger iron affinity than typical siderophores produced by fungi. Minimum inhibitory concentration studies against 8 types of fungi including 37 strains showed that the PLL-DHBA iron chelator exhibited a broad-spectrum antifungal effect. Moreover, PLL-DHBA was even more potent than some traditional antifungal drugs for certain drug-resistant fungi.

The fabrication of chemically stable and high-permeance polymeric membranes, compatible with both polar and nonpolar solvents, for use in solvent filtration is reported. Herein, poly(divinylbenzene-co-perfluorodecyl acrylate) (poly(DVB-co-PFDA) nanoparticles (NPs) are synthesized and integrated into the active layer of a thin-film composite membrane, constructing a thin-film nanocomposite (TFN) membrane. The TFN membranes demonstrate stability in organic solvent and exhibit permeance in the range 13.7 L/(m2 h bar) for acetonitrile, with a molecular weight cutoff of ∼328 Da for the solute. The use of polymeric NPs, compatible with the polyamide layer of the membranes, is the main reason behind the improved performance.

Adhesion between fillers and a polymeric matrix is an essential characteristic for mixed-matrix membranes for molecular separation to avoid defects and cavities that would decrease selectivity. We demonstrate here how solution rheology can be an excellent tool to identity polymer–filler pairs with strong interaction. The investigated system was polytriazole with and without hydroxyl functionalization (PTA-OH and PTA) and ZIF-8. ZIF-8/PTA-OH forms stable gels even with a small filler content, which was investigated under increasing shear rates and different temperatures, while analogous systems without OH functionalization do not gel. The investigations were supported by spectroscopic methods, electron microscopy, and dynamic mechanical analysis of the final solid film. While small ZIF contents lead to sensitive changes in the solution viscosity, only minor changes in the Fourier transform infrared and NMR spectra were detected for the same system. The good adhesion between PTA-OH and ZIF-8 could be seen by electron microscopy, while the analogous PTA/ZIF-8 composites provided films with poor matrix–filler adhesion and undesired cavities. The methods described in this work can be extended as useful tools in the development of composites such as mixed-matrix membranes applied to a large variety of currently available metal–organic frameworks and polymers.

Organic semiconducting materials with a low charge carrier mobility cannot properly act as a channel layer at low voltages for organic field-effect transistors (OFETs). Here, we demonstrate that an n-type conjugated polymer, poly[{5,5,11,11-tetrakis(5-(2-ethylhexyl)thiophene-2-yl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene}-co-{2,7-bis(2-octyldodecyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone}] (PIDTT-NDI), works as an n-channel layer at ≤5 V under light illumination, even though the devices are unable to operate as a transistor in the dark at low voltages. PIDTT-NDI layers with three different thicknesses (t = 50, 70, and 100 nm) are placed on poly(methyl methacrylate) (PMMA) gate-insulating layers in the OFET geometry of bottom-gate and top-source/drain electrodes. Two individual monochromatic light with wavelengths (λ) of 434 and 754 nm, which are chosen from the main peaks in the optical absorption spectra of the PIDTT-NDI films, are employed as a photoexcitation source. The results show that the light illumination delivers proper output and transfer curves of typical n-channel OFETs at ≤5 V, and the electrical conductance of devices gradually increased with the light intensity. In particular, a remarkable enhancement in the photosensitivity (ca. 14,000% at λ = 434 nm) is achieved for the OFETs with the 100 nm-thick PIDTT-NDI layers due to the extremely low drain current level in the dark (5 V).

In this study, a simple one-step preparation of polypyrrole (PPy) assisted by an organic dye, acriflavine hydrochloride (AF), was investigated. The presence of a dye resulted in the development of PPy nanofibers with the conductivity enhanced up to 14 S cm–1. The structural analysis by Fourier-transform infrared and Raman spectroscopies confirmed the interaction of the AF with PPy. As far as the electrochemical activity of PPy is concerned, the gravimetric capacitance increased up to 85 F g–1 with the help of a AF. Additionally, a substantial improvement in the antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria for all the PPy-containing organic dye was achieved. The conductivity, morphology, capacitance, and remarkable antibacterial properties of PPy tuned by an organic dye enable applications wherever the electroconductivity and antibacterial activity should meet requirements, for example, wound healing, electrochemical sensors, bioactuators, or even regenerative medicine.

Here, we describe a facile route to the synthesis of enzymatically active highly fabricable plastics, where the enzyme is an intrinsic component of the material. This is facilitated by the formation of an electrostatically stabilized enzyme–polymer surfactant nanoconstruct, which, after lyophilization and melting, affords stable macromolecular dispersions in a wide range of organic solvents. A selection of plastics can then be co-dissolved in the dispersions, which provides a route to bespoke 3D enzyme plastic nanocomposite structures using a wide range of fabrication techniques, including melt electrowriting, casting, and piston-driven 3D printing. The resulting constructs comprising active phosphotriesterase (arPTE) readily detoxify organophosphates with persistent activity over repeated cycles and for long time periods. Moreover, we show that the protein guest molecules, such as arPTE or sfGFP, increase the compressive Young’s modulus of the plastics and that the identity of the biomolecule influences the nanomorphology and mechanical properties of the resulting materials. Overall, we demonstrate that these biologically active nanocomposite plastics are compatible with state-of-the-art 3D fabrication techniques and that the methodology could be readily applied to produce robust and on-demand smart nanomaterial structures.

Biodegradable polymersomes that can potentially be employed in drug delivery systems were fabricated by blending poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide) (PLLA-PEG-PLLA) and poly(d-lactide)-b-poly(ethylene glycol)-b-poly(d-lactide) (PDLA-PEG-PDLA) block copolymers in a weight ratio of 1:1 in an aqueous solution. A series of amphiphilic PLLA-PEG-PLLA and PDLA-PEG-PDLA triblock copolymers were synthesized with different hydrophobic chain lengths through ring-opening polymerization. The self-assembly of pure PLLA-PEG-PLLA and an equimolar mixture of enantiomers of PLLA-PEG-PLLA and PDLA-PEG-PDLA was investigated by transmission electron microscopy, X-ray diffraction, and dynamic light scattering. Various nanostructures including spherical micelles, worm-like micelles, and vesicles were obtained by controlling the hydrophobic chain length and the incubation temperature. In the pure PLLA-PEG-PLLA systems, the hydrophobic–hydrophilic balance dominated the self-assembled morphologies. In equimolar enantiomer mixtures, self-assembled morphologies were greatly affected by the formation of the PLLA-PDLA stereocomplex (SC). There was an inverse correlation between the SC crystallinity and the curvature of the self-assembled structures─the higher the SC content, the smaller the curvature. This rule was not applicable when the SC content was too high (≳50%), which produced spherical micelles as the main nanostructures. Since the SC-induced self-assembly could be controlled by changing the incubation temperature, the polymersomes can potentially be used in many applications, such as nanoreactors and nanovehicles.

The cross-linking between epoxidized linseed oil (ELO) and suberin has been investigated. Suberin is the major component of cork which can be extracted by hydrolysis. In this study, ELO was cross-linked with suberin with the aim to make fully biobased and nontoxic thermosets without addition of catalysts and to valorize cork coproducts. Polymerization mechanisms were investigated by Fourier transform infrared, rheology, and advanced isoconversional kinetic analysis. Finally, thermomechanical properties have been studied by thermogravimetric analysis, dynamic mechanical analysis, and tensile tests. These experiments highlight that cross-linked ELO/suberin films have a wide relaxation temperature range and a tunable glass transition temperature (Tg) between 57 and 66 °C depending of the suberin ratio in the reaction medium.

The incorporation of fibers into polymers is a well-known route for realizing composite materials with improved strength, stiffness, and toughness. Cellulose nanofibrils (CNFs) are a promising reinforcement because of their high aspect ratio, high specific stiffness and specific strength, and transparency and the fact that they are derived from renewable and sustainable sources. Here, we demonstrate the application of CNFs for the reinforcement of continuous polymer fibers (filaments) to achieve a concurrent enhancement of strength, stiffness, and fracture toughness. Poly(methyl methacrylate) (PMMA)-CNF composite fibers with 0 to 3 wt % CNFs were made by solvent blending and melt-spinning/drawing techniques, resulting in fibers with diameters ranging from 200 to 300 μm. The processing route was developed to overcome challenges presented by the combination of high processing temperatures of PMMA and the low thermal stability of CNFs as well as the formation of a percolated CNF network and low volume fractions. Fourier transform infrared (FTIR) spectroscopy was used to understand the alignment of PMMA and CNFs in the fibers. The strength and Young’s modulus of the fibers were characterized by tensile testing, and the fracture toughness was measured via notched fiber tests. The addition of low-weight fractions (<3%) of CNFs increased Young’s modulus by 35% and yield strength by 19% compared to neat PMMA fibers. Along with this increase in stiffness and strength, the incorporation of 1 wt % CNF led to a doubling of the fracture toughness. FTIR results and imaging of the fracture surfaces provided insight into toughening mechanisms.