Chitosan/vanillin/polydimethylsiloxane scaffolds with tunable stiffness for muscle cell proliferation.

The mechanical properties of scaffolds can significantly influence cell behavior. We propose a methodology for producing chitosan and vanillin-crosslinked chitosan films with tunable mechanical properties to be applied as scaffolds for C2C12 myoblasts. In this approach, aqueous polydimethylsiloxane (PDMS) elastomeric dispersions were prepared using polysorbate 20 as emulsifier.

Droplet evaporation on super liquid-repellent surfaces: A controllable approach for supraparticle fabrication.

Supraparticles are agglomerates of nano- and/or microparticles with sizes ranging from tens to hundreds of microns, making them more accessible for handling and recovery than the building blocks. Supraparticles not only inherit the properties and functions of primary particles but also exhibit characteristics such as high porosity, large specific surface area, and improved functionalities, which can be attributed to the synergism, coupling, and co-localization among the constituents. Therefore, supraparticles hold promising applications in catalysis, drug delivery, sensing, etc.

Surface-Templated Polymer Microparticle Synthesis Based on Droplet Microarrays.

Polymer microparticle synthesis based on the surface-templated method is a simple and environmentally friendly method to produce various microparticles. Unique particles with different compositions can be fabricated by simply annealing a polymer on a liquid-repellent surface. However, there are hurdles to producing particles of homogeneous sizes with large quantities and varying the shape of particles.

Preparation of Water-Soluble Polyion Complex (PIC) Micelles with pH-Responsive Carboxybetaine Block.

A dual zwitterionic diblock copolymer (MC) consisting of poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC, M) and poly(3-((2-(methacryloyloxy)ethyl) dimethylammonio) propionate) (PCBMA, C) is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. A double hydrophilic diblock copolymer (MS) consist of PMPC and anionic poly(3-sulfopropyl methacrylate potassium salt) (PMPS, S) is synthesized via RAFT. The degrees of polymerization of each block are 100.

Effects of Gas Layer Thickness on Capillary Interactions at Superhydrophobic Surfaces.

Strongly attractive forces act between superhydrophobic surfaces across water due to the formation of a bridging gas capillary. Upon separation, the attraction can range up to tens of micrometers as the gas capillary grows, while gas molecules accumulate in the capillary. We argue that most of these molecules come from the pre-existing gaseous layer found at and within the superhydrophobic coating.

Structure Formation in Supraparticles Composed of Spherical and Elongated Particles.

We studied the evaporation-induced formation of supraparticles from dispersions of elongated colloidal particles using experiments and computer simulations. Aqueous droplets containing a dispersion of ellipsoidal and spherical polystyrene particles were dried on superamphiphobic surfaces at different humidity values that led to varying evaporation rates. Supraparticles made from only ellipsoidal particles showed short-range lateral ordering at the supraparticle surface and random orientations in the interior regardless of the evaporation rate.

Durable, Ultrathin, and Antifouling Polymer Brush Coating for Efficient Condensation Heat Transfer.

Heat exchangers are made of metals because of their high heat conductivity and mechanical stability. Metal surfaces are inherently hydrophilic, leading to inefficient filmwise condensation. It is still a challenge to coat these metal surfaces with a durable, robust, and thin hydrophobic layer, which is required for efficient dropwise condensation.

Nanofilament-Coated Superhydrophobic Membranes Show Enhanced Flux and Fouling Resistance in Membrane Distillation.

Membrane distillation (MD) is an important technique for brine desalination and wastewater treatment that may utilize waste or solar heat. To increase the distillation rate and minimize membrane wetting and fouling, we deposit a layer of polysiloxane nanofilaments on microporous membranes. In this way, composite membranes with multiscale pore sizes are created.

A super liquid-repellent hierarchical porous membrane for enhanced membrane distillation.

Membrane distillation (MD) is an emerging desalination technology that exploits phase change to separate water vapor from saline based on low-grade energy. As MD membranes come into contact with saline for days or weeks during desalination, membrane pores have to be sufficiently small (typically <0.2 µm) to avoid saline wetting into the membrane.

Evaporation-driven Supraparticle Synthesis by Self-Lubricating Colloidal Dispersion Microdrops.

The surface-templated evaporation-driven (S-TED) method that uses liquid-repellent surfaces has attracted considerable attention for its use in fabricating supraparticles of defined shape, size, and porosity. However, challenges in achieving mass production have impeded the widespread adoption of the S-TED method. To overcome this limit, we introduce an evaporation-driven "multiple supraparticle" synthesis by drying arrays of self-lubricating colloidal dispersion microdrops.

Method to Measure Surface Tension of Microdroplets Using Standard AFM Cantilever Tips.

Surface tension is a physical property that is central to our understanding of wetting phenomena. One could easily measure liquid surface tension using commercially available tensiometers (e.g.

When crystals flow.

Semicrystalline polymers are solids that are supposed to flow only above their melting temperature. By using confinement within nanoscopic cylindrical pores, we show that a semicrystalline polymer can flow at temperatures below the melting point with a viscosity intermediate to the melt and crystal states. During this process, the capillary force is strong and drags the polymer chains in the pores without melting the crystal.

Effects of liquid surface tension on gas capillaries and capillary forces at superamphiphobic surfaces.

The formation of a bridging gas capillary between superhydrophobic surfaces in water gives rise to strongly attractive interactions ranging up to several micrometers on separation. However, most liquids used in materials research are oil-based or contain surfactants. Superamphiphobic surfaces repel both water and low-surface-tension liquids.

Hierarchically Branched Siloxane Brushes for Efficient Harvesting of Atmospheric Water.

Atmospheric water harvesting is considered a viable source of freshwater to alleviate water scarcity in an arid climate. Water condensation tends to be more efficient on superhydrophobic surfaces as the spontaneous coalescence-induced droplet jumping on superhydrophobic surfaces enables faster condensate removal. However, poor water nucleation on these surfaces leads to meager water harvest.

Plasma-Induced Superhydrophobicity as a Green Technology for Enhanced Air Gap Membrane Distillation.

Superhydrophobicity has only recently become a requirement in membrane fabrication and modification. Superhydrophobic membranes have shown improved flux performance and scaling resistance in long-term membrane distillation (MD) operations compared to simply hydrophobic membranes. Here, we introduce plasma micro- and nanotexturing followed by plasma deposition as a novel, dry, and green method for superhydrophobic membrane fabrication.

Drawing liquid bridges from a thin viscous film.

When a particle, such as dust, contacts a thin liquid film covering a surface it is trapped by the liquid. This effect is caused by the formation of a meniscus, resulting in a capillary force that makes the particle adhere to the surface. While capillary adhesion is well-characterised in static situations, the dynamic formation of the liquid bridge after the initial contact is highly intricate.

Squeezing Drops: Force Measurements of the Cassie-to-Wenzel Transition.

Superhydrophobic surfaces have long been the center of attention of many researchers due to their unique liquid repellency and self-cleaning properties. However, these unique properties rely on the stability of the so-called Cassie state, which is a metastable state with air-filled microstructures. This state tends to transit to the stable Wenzel state, where the inside of the microstructures eventually wets.

Mechanisms of detachment in fibrillar adhesive systems.

Several creatures can climb on smooth surfaces with the help of hairy adhesive pads on their legs. A rapid change from strong attachment to effortless detachment of the leg is enabled by the asymmetric geometry of the tarsal hairs. In this study, we propose mechanisms by which the hairy pad can be easily detached, even when the hairs possess no asymmetry.

Mechanically Robust and Flame-Retardant Superhydrophobic Textiles with Anti-Biofouling Performance.

The attachment of bio-fluids to surfaces promotes the transmission of diseases. Superhydrophobic textiles may offer significant advantages for reducing the adhesion of bio-fluids. However, they have not yet found widespread use because dried remnants adhere strongly and have poor mechanical or chemical robustness.

Spontaneous Charging of Drops on Lubricant-Infused Surfaces.

When a drop of a polar liquid slides over a hydrophobic surface, it acquires a charge. As a result, the surface charges oppositely. For applications such as the generation of electric energy, lubricant-infused surfaces (LIS) may be important because they show a low friction for drops.

Vapor Lubrication for Reducing Water and Ice Adhesion on Poly(dimethylsiloxane) Brushes.

Fast removal of small water drops from surfaces is a challenging issue in heat transfer, water collection, or anti-icing. Poly(dimethylsiloxane) (PDMS) brushes show good prospects to reach this goal because of their low adhesion to liquids. To further reduce adhesion of water drops, here, the surface to the vapor of organic solvents such as toluene or n-hexane is exposed.

High-throughput synthesis of CeO nanoparticles for transparent nanocomposites repelling Pseudomonas aeruginosa biofilms.

Preventing bacteria from adhering to material surfaces is an important technical problem and a major cause of infection. One of nature's defense strategies against bacterial colonization is based on the biohalogenation of signal substances that interfere with bacterial communication. Biohalogenation is catalyzed by haloperoxidases, a class of metal-dependent enzymes whose activity can be mimicked by ceria nanoparticles.

Charging of drops impacting onto superhydrophobic surfaces.

When neutral water drops impact and rebound from superhydrophobic surfaces, they acquire a positive electrical charge. To measure the charge, we analyzed the trajectory of rebounding drops in an external electric field by high-speed video imaging. Although this charging phenomenon has been observed in the past, little is known about the controlling parameters for the amount of drop charging.

Clathrate Adhesion Induced by Quasi-Liquid Layer.

The adhesive force of clathrates to surfaces is a century-old problem of pipeline blockage for the energy industry. Here, we provide new physical insight into the origin of this force by accounting for the existence of a quasi-liquid layer (QLL) on clathrate surfaces. To gain this insight, we measure the adhesive force between a tetrahydrofuran clathrate and a solid sphere.

Controlling supraparticle shape and structure by tuning colloidal interactions.

Hypothesis: Assembly of colloids in drying colloidal suspensions on superhydrophobic surface is influenced by the colloidal interactions, which determine the shape and interior structure of the assembled supraparticle. The introduction of salt (electrolyte) into the assembly system is expected to influence the colloid interactions and packing during the evaporation process. Hence, both the outer shape and internal structure of supraparticles should be controlled by varying salt concentrations.