Controlling and characterising the deposits from polymer droplets containing microparticles and salt

It is very well known that as suspension droplets evaporate, a pinned contact line leads to strong outwards capillary flow resulting in a robust coffee ring-stain at the periphery of the droplet. Conversely tall pillars are deposited in the centre of the droplet when aqueous droplets of poly(ethylene oxide) evaporate following a boot-strapping process in which the contact line undergoes fast receding, driven by polymer precipitation. Here we map out the phase behaviour of a combined particle-polymer system, illustrating a range of final deposit shapes, from ring-stain to flat deposit to pillar. Deposit topologies are measured using profile images and stylus profilometery, and characterised using the skewness of the profile as a simple analytic method for quantifying the shapes: pillars produce positive skew, flat deposits have zero skew and ring-stains have a negative value. We also demonstrate that pillar formation can be disrupted using potassium sulphate salt solutions, which change the water from a good solvent to a thetapoint solvent, consequently reducing the size of the polymer coils. This inhibits polymer crystallisation, interfering with the bootstrap process and ultimately preventing pillars from forming. Again, the deposit shapes are quantified using the skew parameter

Impact of clay particle reattachment on suffusion of sand-clay mixtures

The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion; however, if the detached clay particles are subjected to reattachment, the degree of suffusion may be less significant. This study investigates the impact of clay particle reattachment on suffusion of sand-clay mixtures through laboratory soil-column experiments. The observed breakthrough curves (BTCs) of kaolinite, illite, and montmorillonite for 5 different column lengths (3 in, 6 in, 9 in, 12 in, and 18 in; 1 in = 2.54 cm) indicated that a higher breakthrough concentration was observed as the column length (L) decreased for kaolinite and illite, whereas a reverse trend was observed for montmorillonite. In addition, the increase in the fraction of filtrated clay particles (Me) with an increase in L (Me = 10.42% for L = 3 in and Me = 3.59% for L = 18 in) for the sand-illite mixture indicated that the reattachment effect became more significant as the travel length of detached clay particles increased. The observed BTCs, retention profiles after injection, and fraction of filtrated clay presented herein suggest the need to incorporate the reattachment effect when assessing the suffusion of clay-containing soils

An Experimental and Analytical Study on the Deflection Behavior of Precast Concrete Beams with Joints

The use of precast concrete modular construction in the replacement and rebuilding of old structures has recently increased. However, the joints between modules in this type of construction exhibit special behavior that should be considered when analyzing the behavior of modular members. Both stability and serviceability should be studied; however, existing research has only addressed the former. Research regarding serviceability, involving deflection and crack development and propagation, is lacking. This study considers the difference in strength between on-site cast and precast segmental concrete to accurately evaluate the deflection of precast concrete flexural members with joints within the lapped splice. In addition, to reflect an initial crack, the deflection is calculated and evaluated by reflecting the effect of tension-stiffening and subsequently redefining the attached transmission lengths of the left and right sides of the cracked surface as a new cracked region. As a result of explicitly including joint behavior which is considered attached transmission length and characteristic by concrete strength, a more accurate calculation of deflection is developed

Enhancing effect of sodium butyrate on phosphatidylserine–liposome-induced macrophage polarization

© 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Object: Phosphatidylserine-containing liposomes (PSLs) can mimic the immunomodulatory effects of apoptotic cells by binding to the phosphatidylserine receptors of macrophages. Sodium butyrate, an antiinflammatory short-chain fatty acid, is known to facilitate the M2 polarization of macrophages. This study aimed to investigate the effect of sodium butyrate on PSLs-induced macrophage polarization. Methods: PSLs physical properties and cellular uptake tests, reverse transcription–quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence staining, and flow cytometry analysis were performed to assess the polarization-related indicators of M1/M2 macrophages. Results: The results showed that sodium butyrate did not affect the size and cellular uptake of PSLs. For M1 macrophage polarization, sodium butyrate significantly intensified the antiinflammatory function of PSLs, inhibiting LPS-induced proinflammatory genes expression, cytokines and enzyme release (tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, and inducible nitric oxide synthase), as well as CD86 (M1 marker) expression. In addition to the enhancing effect of antiinflammation, sodium butyrate also promoted PSL-induced M2 macrophages polarization, especially elevated thymus and activation-regulated chemokine (TARC) and arginase-1 (Arg-1) enzyme levels which are involved in tissue repair. Conclusion: Sodium butyrate enhanced antiinflammatory properties and M2-polarization inducing effect of PSLs. Therefore, sodium butyrate may represent a novel approach to enhance PSL-induced macrophage polarization.N

Graphene-Assisted Zwitterionic Conjugated Polycyclic Molecular Interfacial Layer Enables Highly Efficient and Stable Inverted Perovskite Solar Cells

As an effective strategy to achieve high performance and operational stability in perovskite solar cells (PSCs), numerous studies have been conducted to develop efficient charge transporting materials that possess desirable conductivity, carrier mobility, and stability. Among the great number of candidate materials, graphene has attracted significant attention owing to its remarkable optoelectrical properties and stability. Based on these advantages, in this study, a graphene-assisted electron transport layer (ETL) was developed through functionalization with an n-type semiconducting small molecule, perylene diimide amino N-oxide (PDINO), which simultaneously improved the performance and stability of PSCs. The PDINO-functionalized graphene ETL exhibited suitable energy-level alignment with enhanced carrier mobility, thus resulting in an enhanced power conversion efficiency of 21.2% for the inverted structured PSCs. Moreover, through the hydrophobic surface feature and barrier property of graphene and the pi-pi interaction of PDINO with the underlying layer of PSCs, notably improved operational stability was achieved using the developed functionalized graphene ETL

Diazapentalene-Containing Ultralow-Band-Gap Copolymers for High-Performance Near-Infrared Organic Phototransistors

Because of the limited availability of synthetic strategies and strong acceptor units, constructing new types of low-band-gap donor-acceptor-type copolymers for use in multiple functional applications remains a big challenge. Herein, we report the synthesis, characterization, and optoelectronic applications (i.e., organic field-effect transistors (OFETs) and organic phototransistors (OPTs)) of a novel class of ultralow-band-gap copolymers (PDAP-Fu, PDAP-Th, and PDAP-Se) on the basis of the unique, interesting, yet rarely researched bicyclic 2,5-diazapentalene (DAP) strong acceptor in conjugation with chalcogenophene donors (furan (Fu), thiophene (Th), or selenophene (Se)). All of the copolymers exhibit broad near-infrared (NIR) absorption and optical band gaps as low as similar to 1.0 eV. The effects of the actual chalcogen atoms on the geometry, optical properties, energy levels, and film organization are carefully determined for OFET and OPT applications. Regarding the OFET studies, all of the copolymers show unipolar transport behavior in bottom-gate and top-contact OFETs, and PDAP-Se exhibits the highest hole mobility of 4.76 x 10(-1) cm(2) V-1 s(-1). Besides, investigations of the OPTs indicate that a high photoresponse is achieved for all of the copolymers at a wavelength of 1060 nm in the NIR spectral region combined with an excellent external quantum efficiency (eta) and photodetectivity (D*). This is particularly true for PDAP-Se (eta = 6.56 x 10(4)% and D* = 1.80 x 10(12) Jones). Thus, such ultralow-band-gap copolymers are promising candidates for use in integrated circuits and optoelectronic devices

Effect of the carbon nanotube type on the thermoelectric properties of CNT/Nafion nanocomposites

The effect of different carbon nanotube (CNT) types on the thermoelectric performance of CNT/polymer nanocomposites was studied. Three different kinds of CNTs, single( SWCNTs), few-(FWCNTs) and multi-walled CNTs (MWCNTs), were effectively dispersed in an aqueous solution of Nafion. The electrical properties of the CNT/Nafion nanocomposites were primarily affected by the CNTs since the Nafion acts as an electrically non-conducting matrix, while the thermal conductivity of the nanocomposites was dominated by the Nafion mainly due to weak van der Waals interaction. In this way, electrical and thermal transport can be separated. In all three types of CNTs, both the electrical conductivity and Seebeck coefficient increased as the concentration of CNTs was increased. While the electrical conductivity depends on the type of CNT, the behavior of the Seebeck coefficient was relatively insensitive of the CNT type at high CNT loading. This indicates that high-energy-charges can participate in transport processes irrespective of the type of CNT. It is suggested that FWCNTs and MWCNTs are preferred over SWCNTs in CNT/Nafion nanocomposites for thermoelectric applications

Selective Etching of Si versus Si_1−xGe_x in Tetramethyl Ammonium Hydroxide Solutions with Surfactant

We investigated the selective etching of Si versus Si1−xGex with various Ge concentrations (x = 0.13, 0.21, 0.30, 0.44) in tetramethyl ammonium hydroxide (TMAH) solution. Our results show that the Si1−xGex with a higher Ge concentration was etched slower due to the reduction in the Si(Ge)–OH bond. Owing to the difference in the etching rate, Si was selectively etched in the Si0.7Ge0.3/Si/Si0.7Ge0.3 multi-layer. The etching rate of Si depends on the Si surface orientation, as TMAH is an anisotropic etchant. The (111) and (010) facets were formed in TMAH, when Si was laterally etched in the and directions in the multi-layer, respectively. We also investigated the effect of the addition of Triton X-100 in TMAH on the wet etching process. Our results confirmed that the presence of 0.1 vol% Triton reduced the roughness of the etched Si and Si1−xGex surfaces. Moreover, the addition of Triton to TMAH could change the facet formation from (010) to (011) during Si etching in the -direction. The facet change could reduce the lateral etching rate of Si and consequently reduce selectivity. The decrease in the layer thickness also reduced the lateral Si etching rate in the multi-layer