Ultrasound-responsive liposomes represent a promising strategy for the targeted delivery of therapeutic agents to deep tissues, combining the clinically validated biocompatibility of liposomes with precise spatiotemporal control via ultrasound. While the incorporation of polyethylene glycol-conjugated lipids into liposomal formulations has long been known to enhance ultrasound-triggered release, the mechanistic basis of this enhancement remains poorly understood, hindering the rational design of formulations with enhanced ultrasound-triggered release. To address this, we investigated the proposed hypotheses in the literature, including the influence of the packing parameter, differences in thermal, mechanical, and fluidity properties, as well as structural changes such as micelle formation or bilayer thinning for stealth liposomes containing polyethylene glycol, polycarboxybetaine, or polysarcosine. Our results indicate that PEG-enhanced ultrasound-triggered release cannot be attributed to changes in bulk bilayer properties, including the packing parameter, membrane mechanics, thermal behavior, or fluidity. Moreover, the membrane structure remained unchanged after insonation, with no evidence of micelle ejection or membrane thinning. Instead, experiments and computational simulations suggest that polyethylene glycol-conjugated lipopolymers facilitate sonoporation by rearranging into micelle-like structures at the periphery of ultrasound-induced pores in the lipid bilayer, enabled by their low critical micelle concentration, thereby enhancing the release through these transient openings. Finally, we discuss how these insights could be extended beyond polyethylene glycol lipopolymers to guide the design of liposomes with enhanced ultrasound-triggered release, by shifting optimization from bulk bilayer properties to a sonoporation-oriented framework that integrates computational screening, AI-enabled formulation design, and ultrasound waveform considerations.

Microalloyed low-carbon steels strengthened by vanadium carbide (VC) nanoprecipitates are receiving increasing attention, particularly in the automotive industry. A clear understanding of the nanoprecipitate chemistry is essential for optimizing the alloy composition and processing routes, thereby enhancing the mechanical properties of such advanced steels. The chemical evolution of VC precipitates, especially regarding the incorporation of iron into the nanoprecipitates, remains uncertain. Here, a model vanadium-microalloyed low-carbon steel is studied by atomic-resolution scanning transmission electron microscopy (STEM) techniques. The steel contains nanoscale VC precipitates formed either as interphase precipitates (IP) at the austenite/ferrite interface during the austenite-to-ferrite phase transformation, or as randomly distributed precipitates (RP) in the ferrite matrix during bainite tempering. The first-time observation of carbon sublattice atoms in VC is achieved using integrated differential phase-contrast STEM (iDPC-STEM). Non-equilibrium compositions are identified under both precipitation mechanisms, with no correlation between precipitate size and associated elemental contents. Most interphase VC nanoprecipitates contain higher amounts of not only iron but also manganese compared to random VC nanoprecipitates. Complementary ex-situ small-angle neutron scattering (SANS) analysis and solute-drag effect (SDE) modeling support the co-segregation of iron and manganese into the precipitates. Manganese typically appears to form a core–shell-like structure within VC. Experimental evidence is presented for the SDE-assisted formation of manganese-rich–core (fibrous) interphase VC precipitates, and a mechanism is proposed for iron–manganese co-enrichment in random VC precipitates. This study offers new insights into future strategies to tune nanoprecipitate chemistry in microalloyed steels.

Waterborne and water-reduced coatings are increasing in relevance in many sectors as an alternative to solventborne coatings. In this work, the internal structure of waterborne polymers as a function of colloid particle size is unveiled and directly related to macroscopic water absorption. To this aim, a set of acrylic waterborne films was prepared from dispersions of different colloidal particle sizes (100, 150, and 200 nm) with the same surfactant coverage. Macroscopic water absorption and water affinity were studied by Dynamic vapor sorption (DVS) and immersion tests. Small-Angle Neutron Scattering (SANS) was used to study deuterated water diffusion with time. This revealed the presence of remnant hydrophilic colloid-colloid interphases in all films, independently of the forming colloidal size and annealing conditions. Moreover, fitting of SANS data revealed that water transport in these films happens through surfactant-rich colloid-colloid interphases or through 10 nm-wide hydrophilic paths rich in surfactant aggregates (in the range of 4 nm) when these are present. The presence of the hydrophilic paths explains the higher water uptake measured in waterborne films made from 100 nm colloids, a process so far not previously reported. This study highlights how water diffusion in waterborne films may be engineered through fine control of particle size and film formation conditions.

The broadband resonant spin echo interferometer, Coherent Averaging Neutron Instrument for Spin-echo Interferometry and fUndamental Science (CANISIUS), is presented. CANISIUS is located at the 250 kW Training, Research, Isotopes, General Atomics research facility of the Atominstitut, TU Wien, Austria. It is built in a versatile way, such that it can be operated in both a continuous broadband beam and a pulsed time of flight beam. This versatility also extends to the modes available to the instrument, such as neutron resonant spin echo, spin echo (modulated) small angle neutron scattering, and coherent averaging to produce structured wavefunctions for scattering. The instrument may also be used as an interferometer, to probe fundamental questions in quantum mechanics. In this paper, we detail both the continuous and time of flight options of the instrument. In addition, we demonstrate the applicability of our interferometer to ultra small angle scattering in a white beam. Finally, we demonstrate a new spin echo interferometry tool, which uses incomplete recombination of the two path states to generate composite wavefunctions with special structure. In particular, we show that this method produces neutron wavefunctions that exist in a superposition of two quantum mechanical orbital angular momentum modes, ℓ = ±1. We illustrate that just as this method can be used to generate certain structured waves, it may also be used to characterize the structure of the input wavefunction.

The formation of nanoscale vanadium carbide (VC) precipitates is reported in steels subjected to two different thermal treatments. The thermal treatments lead to either interphase precipitation (IP) or random precipitation (RP). Small-angle neutron scattering measurements coupled with transmission electron microscopy analysis are performed to determine the VC precipitate volume fraction and size distribution. It is seen that the samples exhibiting IP show a higher number density of VC precipitates compared to those undergoing RP. Moreover, a broader size distribution of the precipitate radii is observed in the samples with RP, where lens-shaped nanoscale VC precipitates are found predominantly at grain boundaries (GBs) and sub-grain boundaries (SGBs), with smaller precipitates dispersed within the matrix. It is seen that the addition of carbon and vanadium does not increase the VC precipitate number density when the mechanism of precipitation is IP, whereas an increase in the VC precipitate number density with carbon and vanadium addition is seen in case of RP.

P3HT is a semiconducting polymer widely used in solution-processable photovoltaic research. Measuring the solubility of P3HT in organic solvents is usually an arduous and time-consuming process. Here we report the presence or absence of P3HT nanoparticle agglomeration in optically opaque solutions of P3HT, with concentrations ranging from 6.2 to 22.0 mg·mL⁻¹, in pure chloroform and in chloroform:acetone mixtures, using the neutron scattering technique, Spin-Echo Small Angle Neutron Scattering (SESANS). We demonstrate in-situ that the solubility of P3HT decreases from ∼ 22.0 mg/mL to < 6.2 mg/mL when the amount of acetone in solution increases from 0 vol% to 60 vol%. This work uses the ability of SESANS to probe P3HT nanoparticle aggregates, with dimensions ranging from ∼ 1 to several microns, in P3HT solutions with concentrations above the solubility limit.

We describe an experiment that strongly supports a two-path interferometric model in which the spin-up and spin-down components of each neutron propagate coherently along spatially separated parallel paths in a typical neutron spin-echo small-angle scattering (SESANS) experiment. Specifically, we show that the usual semi-classical, single-path treatment of Larmor precession of a polarized neutron in an external magnetic field predicts a damping as a function of the spin-echo length of the SESANS signal obtained with a periodic phase grating when the transverse width of the neutron wave packet is finite. However, no such damping is observed experimentally, implying either that the Larmor model is incorrect or that the transverse extent of the wave packet is very large. In contrast, we demonstrate theoretically that a quantum-mechanical interferometric model in which the two mode-entangled (i.e., intraparticle entangled) spin states of a single neutron are separated in space when they interact with the grating accurately predicts the measured SESANS signal, which is independent of the wave packet width.

We have designed and realized a temperature and pressure controlled cell for Neutron Reflectometry (NR) and Small Angle Neutron Scattering (SANS) that is compatible with simultaneous optical transmission and resistivity measurements. The cell can accommodate samples up to 102 mm (4 inch) in diameter, can be pressurized from vacuum up to 10 bar gas pressure and the sample temperature can be controlled up to 350°C. The four single crystal quartz windows ensure both a good neutron and optical transmission and hence can be used in combination with in-situ optical transmission measurements. We present the cell and illustrate its performance with a series of neutron reflectometry experiments performed on Ta based thin films under a hydrogen containing atmosphere.