Microplastic Materials for Inhalation Studies: Preparation by Solvent Precipitation and Comprehensive Characterization.

Assessing the inhalation hazard of microplastics is important but necessitates sufficient quantity of microplastics that are representative and respirable (<4 µm). Common plastics are not typically manufactured in such small sizes. Here, solvent precipitation is used to produce respirable test materials from thermoplastics polyurethane (TPU), polyamide (PA-6), polyethylene terephthalate (PET), and low-density polyethylene (LDPE).

Sustainable Design of Structural and Functional Polymers for a Circular Economy.

To achieve a sustainable circular economy, polymer production must start transitioning to recycled and biobased feedstock and accomplish CO emission neutrality. This is not only true for structural polymers, such as in packaging or engineering applications, but also for functional polymers in liquid formulations, such as adhesives, lubricants, thickeners or dispersants. At their end of life, polymers must be either collected and recycled via a technical pathway, or be biodegradable if they are not collectable.

Scalable and Transfer-Free Fabrication of MoS/SiO Hybrid Nanophotonic Cavity Arrays with Quality Factors Exceeding 4000.

We report the fully-scalable fabrication of a large array of hybrid molybdenum disulfide (MoS) - silicon dioxide (SiO) one-dimensional, free-standing photonic-crystal cavities capable of enhancement of the MoS photoluminescence at the narrow cavity resonance. We demonstrate continuous tunability of the cavity resonance wavelength across the entire emission band of MoS simply by variation of the photonic crystal periodicity. Device fabrication started by substrate-scale growth of MoS using chemical vapor deposition (CVD) on non-birefringent thermal oxide on a silicon wafer; it was followed by lithographic fabrication of a photonic crystal nanocavity array on the same substrate at more than 50% yield of functional devices.

Bimolecular crystals with an intercalated structure improve poly(p-phenylenevinylene)-based organic photovoltaic cells.

The exciton dissociation, recombination, and charge transport of bulk heterojunction organic photovoltaic cells (OPVs) is influenced strongly by the nanomorphology of the blend, such as the grain size and the molecular packing. Although it is well known that polymers based on amorphous poly(p-phenylenevinylene) (PPV) have a fundamental limit to their efficiency because of low carrier mobility, which leads to increased recombination and unbalanced charge extraction, herein, we demonstrate that the issue can be overcome by forming bimolecular crystals of an amorphous PPV-based polymer:phenyl-C61 -butyric acid methyl ester (PCBM) intercalated structure. We used amorphous poly(2,5-dioctyloxy-p-phenylene vinylene-alt-2',5'-thienylene vinylene) (PPVTV), which has a simple chemical structure.

Control of charge generation and recombination in ternary polymer/polymer:fullerene photovoltaic blends using amorphous and semi-crystalline copolymers as donors.

Charge generation and recombination processes occurring in ternary photoactive copolymer:copolymer:fullerene blends consisting of different mixing ratios between entirely amorphous and semi-crystalline PPE-PPV copolymers are investigated by transient absorption pump-probe and pump-push photocurrent spectroscopy. The experiments reveal that an excess of semi-crystalline polymer facilitates exciton dissociation into free charge carriers, slows down geminate recombination, and suppresses non-geminate recombination leading to increased short-circuit currents and high fill factors. In contrast, blends utilizing solely the amorphous polymer for their donor phase suffer from a large fraction of sub-nanosecond geminate recombination of interfacially bound charge-transfer states and also from fast non-geminate recombination of free charges, resulting in a significantly reduced photovoltaic performance.