In this study, hierarchical micro/nano-structured transparent superhydrophobic polytetrafluoroethylene (PTFE) films showing a water contact angle (CA) of 168°, a water sliding angle (SA) 90% were prepared on glass substrates via aerosol-assisted chemical vapor deposition (AACVD). Scanning electron microscopy showed the morphology to be rough, composed of both micro and nano sized protrusions. Mechanical testing showed that after impingement from 800 drops of 15 μL water (height = 1 m) or 10 g of sand grains (height = 65 cm), the CA of the transparent PTFE surface was still >150°, still demonstrating excellent superhydrophobicity. The films also showed self-cleaning and anti-corrosion properties. This one-step fabrication is a facile way of producing various kinds of transparent superhydrophobic surfaces.

A simple, economical and effective solution-based chemical vapour deposition (CVD) technique, aerosol-assisted CVD, has been successfully applied to produce inexpensive Cl-doped ZnO films using Zn acetate dihydrate and FeCl₃. X-ray photoelectron spectroscopy and the increase in cell parameters from powder X-ray diffraction determined that Cl had been doped into the wurtzite ZnO lattice. The Cl-doping had a significant effect on the morphology of the thin films synthesised and resulted in an improvement in the visible light transmission and lower electrical resistance (typical resistivities of doped films ∼10⁻² Ω cm). The highest transmittance (% T) of 85% was obtained when 7 mol% FeCl₃ was used in the precursor solution and the lowest resistivity of 4.28 ± 0.41 × 10⁻² Ω cm was obtained with 5 mol% FeCl₃. The greatest photocatalytic activity of stearic acid degradation under UVA irradiation was obtained on using 10 mol% FeCl₃, resulting in the highest formal quantum efficiency (FQE) of 3.0 ± 0.1 × 10⁻⁴ molecule per photon. These films, therefore, display transparent conducting oxide and photocatalytic properties, giving multifunctional characteristics and promising applications.

Highly sensitive flexible tactile sensors with synergistic normal and shear force perception are urgently required for possible grasping, lifting and other in-hand manipulations of robotic hands. Herein, a capacitive 3-D force tactile sensing array inlaid an enhanced porous dielectric layer was presented. The micro-pores were formed through vacuum-assisted infiltration of polydimethylsiloxane (PDMS) solution applying perfluorotributylamine (C12F27N) as sacrificial solvent, meanwhile, using sugar particles mixed up with PDMS-C12F27N emulsion to create extra macro pores. The surface of the sensing array consisted of numbers of pen-cap-like bumps for reliable traction of objects. When normal or shear forces were applied on the surface, the contacted bumps were compressed or declined. The deflections of bumps resulted in possible capacitance variations, which were corresponded to the applied normal and shear forces. Compared with capacitive sensors inlaid an un-patterned solid dielectric layer, the developed sensing array experimentally displayed a high elasticity, a large sensing pressure range (over 250 kPa for normal pressure and over 60 kPa for shear pressures), a high sensitivity (1.63%/kPa and 1.61%/kPa for normal and shear pressure, respectively), a good repeatability and a good structural stability and durability. Finger attached tests validated the proposed tactile sensing array having great potential for all kinds of robotics and prosthetic hand applications.

In this study, superhydrophobic ZnO/Polytetrafluoroethylene (ZnO/PTFE) films with water droplet contact angles (CA) observed as high as 165° and water droplet sliding angles of (SA) <1° have been prepared on glass substrates by RF magnetron sputtering. The PTFE was wrapped on a nano-rod made of a ZnO film with superhydrophobic properties while providing excellent UV resistance compared to hexadecyltrimethoxysilane (HDTMS) hydrophobic agents. The upper surface of the rough ZnO film was coated with PTFE, and most of the underlying coating was bare ZnO, which could well make contact with bacteria. For the Gram-negative strain, E. coli, the cell viability count of the ZnO/PTFE sample (3.5 log reduction, 99.96%) was conspicuously lower than that of the ZnO/HDTMS sample (1.2 log reduction, 93.87%) under 1 h illumination of UV light, which showed that the ZnO/PTFE sample has a better photocatalytic property than the ZnO/ HDTMS films. The ZnO/PTFE films also showed good mechanical robustness, which is an important consideration in their widespread real-world adoption.