We report a robust procedure for preparing superhydrophobic hybrid films on which the advancing contact angle for water is about 165 degrees and the roll-off angle of a 10-muL water droplet is 3 +/- 1 degrees . Dual-size surface roughness, which mimics the surface topology of self-cleaning plant leaves, originates from well-defined silica-based raspberry-like particles that are covalently bonded to an epoxy-based polymer matrix. The roughened surface is chemically modified with a layer of poly(dimethylsiloxane) (PDMS). The robustness and simplicity of this procedure may make widespread applications of so-prepared superhydrophobic films possible.

We report a biomimetic procedure to prepare superhydrophobic cotton textiles. By in situ introducing silica particles to cotton fibers to generate a dual-size surface roughness, followed by hydrophobization with polydimethylsiloxane (PDMS), normally hydrophilic cotton has been easily turned superhydrophobic, which exhibits a static water contact angle of 155 degrees for a 10 microL droplet. The roll-off angle of water droplets depends on the droplet volume, ranging from 7 degrees for a droplet of 50 microL to 20 degrees for a 7 microL droplet. When a perfluoroalkyl chain is introduced to the silica particle surface, the superhydrophobic textile also becomes highly oleophobic, as demonstrated by a static contact angle of 140 degrees and a roll-off angle of 24 degrees for a 15 microL sunflower oil droplet.

Common cotton textiles are hydrophilic and oleophilic in nature. Superhydrophobic cotton textiles have the potential to be used as self-cleaning fabrics, but they typically are not super oil-repellent. Poor oil repellency may easily compromise the self-cleaning property of these fabrics. Here, we report on the preparation of superoleophobic cotton textiles based on a multilength-scale structure, as demonstrated by a high hexadecane contact angle (153 degrees for 5 microL droplets) and low roll-off angle (9 degrees for 20 microL droplets). The multilength-scale roughness was based on the woven structure, with additional two layers of silica particles (microparticles and nanoparticles, respectively) covalently bonded to the fiber. Superoleophobicity was successfully obtained by incorporating perfluoroalkyl groups onto the surface of the modified cotton. It proved to be essential to add the nanoparticle layer in achieving superoleophobicity, especially in terms of low roll-off angles for hexadecane.

We present the first surfactant-free inverse emulsion polymerization by using organically modified clay platelets as stabilizers. Colloidally stable inverse Pickering emulsions of aqueous acrylamide (AAm) or 2-hydroxyethyl methacrylate (HEMA) in cyclohexane stabilized by hydrophobic Cloisite 20A (MMT20) were prepared. With both oil-soluble 2,2‘-azobis(isobutyronitrile) (AIBN) and water-soluble 2,2‘-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (VA-086) as initiators, inverse latexes in the size range of 700−980 nm were successfully obtained. It has been revealed by SEM and cryo-TEM that the latexes were stabilized by hydrophobic clays, as exemplified by the rugged surface of the particles. It was shown from thermogravimetric analysis (TGA) that all the clay platelets were incorporated into the composite particles, and in partially exfoliated state as indicated by X-ray diffraction study.

Herein, we developed a nanocomposite membrane with synergistic photodynamic therapy and photothermal therapy antibacterial effects, triggered by a single near-infrared (NIR) light illumination. First, upconversion nanoparticles (UCNPs) with a hierarchical structure (UCNPs@TiO2) were synthesized, which use NaYF4:Yb,Tm nanorods as the core and TiO2 nanoparticles as the outer shell. Then, nanosized graphene oxide (GO), as a photothermal agent, was doped into UCNPs@TiO2 core–shell nanoparticles to obtain UCNPs@TiO2@GO. Afterward, the mixture of UCNPs@TiO2@GO in poly­(vinylidene) fluoride (PVDF) was applied for electrospinning to generate the nanocomposite membrane (UTG-PVDF). Generation of reactive oxygen species (ROS) and changes of temperature triggered by NIR action were both investigated to evaluate the photodynamic and photothermal properties. Upon a single NIR light (980 nm) irradiation for 5 min, the nanocomposite membrane could simultaneously generate ROS and moderate temperature rise, triggering synergistic antibacterial effects against both Gram-positive and -negative bacteria, which are hard to be achieved by an individual photodynamic or photothermal nanocomposite membrane. Additionally, the as-prepared membrane can effectively restrain the inflammatory reaction and accelerate wound healing, thus exhibiting great potentials in treating infectious complications in wound healing progress.

Dual-functional antifogging/antimicrobial polymer coatings were prepared by forming a semi-interpenetrating polymer network (SIPN) of partially quaternized poly(2-(dimethylamino)ethyl methacrylate-co-methyl methacrylate) and polymerized ethylene glycol dimethacrylate network. The excellent antifogging behavior of the smooth coating was mainly attributed to the hydrophilic/hydrophobic balance of the partially quaternized copolymer, while the covalently bonded, hydrophobic quaternary ammonium compound (5 mol % in the copolymer) rendered the coating strongly antimicrobial, as demonstrated by the total kill against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli. The antimicrobial action of the SIPN coating was based on contact killing, without leaching of bactericidal species, as revealed by a zone-of-inhibition test. This type of dual-functional coating may find unique applications where both antimicrobial and antifogging properties are desired.

The kinetics of CuBr-mediated homogeneous atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) using 2-hydroxyethyl-2-bromoisobutyrate (HEBIB) as initiator and N-(n-hexyl)pyridylmethanimine (NHPMI) as ligand was investigated. The experimental results showed that initially added Cu(II) can have strong effects on the kinetics of the ATRP depending on the [Cu(II)]0/[Cu(I)]0 ratio. When ≤10% Cu(II) relative to Cu(I) was added at the beginning of the polymerization, the kinetics can be well described by Fischer's equation (ln([M]0/[M]) ∝ t 2/3). The obtained reaction orders for initiator, Cu(I) and Cu(II), are quite close to or the same as those in Fischer's equation, verifying the applicability of Fischer's equation in ATRP systems. On the other hand, when [Cu(II)]0/[Cu(I)]0 ≥ 0.1, the kinetics can be well interpreted by Matyjaszewski's equation (ln([M]0/[M]) ∝ t). The polymerization rate shows almost first order with respect to the concentrations of initiator and Cu(I) and inverse first order with respect to the concentration of Cu(II), suggesting that the “self-regulation” and radical termination becomes unimportant for the ATRP process when enough Cu(II) is added at the beginning of the reaction. This result is of great potential importance for better control of ATRP systems. Besides, the equilibrium constant K eq and termination constant k t of the ATRP system at 90 °C were determined to be 7.2 × 10-8 and 8.9 × 107 M-1 s-1, respectively.

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