We report the assembly of metal-polyphenol complex (MPC) films and capsules through the sequential deposition of iron­(III) ions (Fe(III)) and a natural polyphenol, tannic acid (TA), driven by metal–ligand coordination. Stable Fe(III)/TA films and capsules were formed, indicating lateral and longitudinal cross-linking of TA by Fe(III) in the film structure. Quartz crystal microbalance, ultraviolet–visible (UV-vis) spectrophotometry, and X-ray photoelectron spectroscopy were carried out to quantitatively analyze the film growth. A comparison of the MPC capsules prepared through multistep assembly with those obtained through one-step deposition, as reported previously [Ejima et al., Science 2013, 341, 154–156], reveals substantial differences in the nature of complexation and in their physicochemical properties, including permeability, stiffness, and degradability. This study highlights the importance of engineering MPC films with different properties through implementing different assembly methods.

A novel fabrication process is presented using monodisperse PMMA latex particles to facilitate controlled microvoid formation. This results in hierarchically rough surfaces exhibiting ∼90% optical transmission while retaining water contact angle (θ) of 170°. Synchrotron small angle X-ray scattering, AFM roughness measurements, and theoretical modeling suggests that a surface morphology with fractal dimension of ∼2.6 and R a < 400 nm allows for the optimum coupling of roughness-induced superhydrophobicity and optical transparency. Interestingly, surfaces of vastly different roughness (R rms) exhibited similar water contact angles, highlighting a limitation of traditional AFM roughness measurements in quantifying multiscale rough surfaces. An alternate method considering fractal dimension is presented as a more complete quantifier of hierarchical surface morphology in relation to surface wetting behavior.

Crosslinked polyelectrolyte multilayer membranes are synthesized with salt rejection values approaching those of commercial desalination membranes, but with increased chlorine resistance. The membranes are fabricated directly onto porous commercial substrates. Subsequent crosslinking of the polycation layers with glutaraldehyde leads to NaCl rejections of up to 97%, while the incorporation of a highly sulfonated polysulfone polyanion leads to high chlorine resistance.

We report engineered hydrogel thin-films with varying degrees of covalent crosslinking, which demonstrate enhanced HeLa cell adhesion with decreasing film stiffness. This trend is contrary to previous findings for tumour cell adhesion on hydrogel substrates, and is attributed to the extremely soft nature of the films studied, allowing for a greater cell/film contact area and the development of adhesive focal contacts. Adhesion based on mechanical tuning of the film was decoupled from chemical effects through characterisation and analysis of film surface roughness, hydrophobicity and charge. Control over cellular adhesion, differentiation, migration and recolonisation through substrate modification has recently emerged as a topic of considerable research effort. 1-5 Understanding these interactions allows for regulation of stem-cell 65

Surfaces consisting of sub micron holes (0.420-0.765 μm) engineered into nanoparticle (12 nm) coatings were examined for marine antifouling behaviour that defines early stage settlement. Immersed surfaces were found to be resistant to a 5-hour attachment assay of Amphora coffeaeformis, a marine organism commonly found in abundance on fouled substrates such as foul-releasing paints and self-polishing coatings. Attachment inhibition was attributed to the accessibility of diatoms to the surface. This was governed by the size and morphology of trapped interfacial air pockets measured in-situ using synchrotron small angle x-ray scattering. Surfaces containing larger pores (0.765 μm) exhibited the highest resistance. Macroscopic wettability via contact angle measurements however remained at 160° and sliding angle of &lt; 5° and was found to be independent of pore size and not indicative of early stage fouling behaviour. The balance of hierarchical nano/micro length scales was critical in defining the early stage stability of biofouling character of the interface.