Omniphobic Metal Surfaces with Low Contact Angle Hysteresis and Tilt Angles.

Various metal (Al, Ti, Fe, Ni, and Cu) surfaces with native oxide layers were rendered "omniphobic" by a simple thermal treatment of neat liquid trimethylsiloxy-terminated polymethylhydrosiloxanes (PMHSs) with a range of different molecular weights (MWs). Because of this treatment, the PMHS chains were covalently attached to the oxidized metal surfaces, giving 2-10 nm thick PMHS layers. The resulting surfaces were fairly smooth, liquid-like, and showed excellent dynamic omniphobicity with both low contact angle hysteresis (≲5°) and substrate tilt angles (≲8°) toward small-volume liquid drops (5 µL) with surface tensions ranging from 20.5 to 72.8 mN/m. Droplet mobility was improved overall as a result of heating the substrates to 70 °C. The reaction kinetics and final dynamic dewetting properties were found to be not dependent of the types of metals employed or MWs of PMHS, but mainly dominated by both reaction temperatures and reaction times.

Surface roughness rather than surface chemistry essentially affects insect adhesion.

The attachment ability of ladybird beetles Coccinella septempunctata was systematically investigated on eight types of surface, each with different chemical and topographical properties. The results of traction force tests clearly demonstrated that chemical surface properties, such as static/dynamic de-wettability of water and oil caused by specific chemical compositions, had no significant effect on the attachment of the beetles. Surface roughness was found to be the dominant factor, strongly affecting the attachment ability of the beetles.

Lamination of alumina membranes to polymer surfaces: thick, hard, transparent, crack-free alumina films on polymers with excellent adhesion.

Hard and transparent alumina (Al(2)O(3)) films with thicknesses in the range of 500 nm to 5 µm were successfully formed on polymethylmethacrylate (PMMA) and polystyrene (PS) surfaces. Our process is based on a lamination of anodized aluminum membranes (AAMs) to the polymer surfaces, followed by chemical etching. Because of capillary force, molten PS and liquid PMMA precursor were successfully pulled into the nanopores (10 nm diameter) within the Al(2)O(3) layers and solidified by cooling or polymerization, respectively. Our resulting AAM-laminated surfaces exhibited excellent adhesion and surface mechanical properties similar to those of fused silica, remaining crack-free and transparent even with Al(2)O(3) thicknesses exceeding 1 µm.

Hydrophobic/superhydrophobic oxidized metal surfaces showing negligible contact angle hysteresis.

Dynamic wettability of oxidized metal (aluminum and titanium) surfaces could be tuned by chemical vapor deposition (CVD) of 1,3,5,7-tetramethylcyclotetrasiloxane (D(4)(H)). This facile CVD method produces not only monomeric layers but also particulate films by changing the CVD temperature, resulting in a marked difference in the final wetting properties. In the samples prepared at 80°C for ~3 days, D(4)(H) layers with thicknesses of ~0.5 nm were formed on the surfaces without discernible change in surface morphology, as evidenced by X-ray photoelectron spectroscopy and atomic force microscopy. After this D(4)(H) monomeric layer formation, the hydrophilic oxidized aluminum and titanium surfaces became hydrophobic (advancing/receding water contact angles (θ(A)/θ(R))=102-104°/99-102°) showing essentially negligible contact angle hysteresis. Performing CVD of D(4)(H) at 180°C for ~1 day produced opaque film with particulate morphologies with diameters in the range of 500 nm to 4 µm observed on the surfaces. This geometric morphology enhanced the surface hydrophobicity (θ(A)/θ(R)=163°/160-161°). Droplets on these negligible-hysteresis surfaces moved very easily without "pinning".

New objective evaluation method for functional bowel disorder using video capsule endoscopy.

AIM: The aim of the present study was to use video capsule endoscopy (VCE) to objectively evaluate bowel movements in patients with irritable bowel syndrome (IBS) compared with healthy volunteers. METHODS: Subjects were nine healthy volunteers (group A) and five IBS patients (group B) whose VCE reached the cecum within the examination time. As the darkest component in an image of VCE is the lumen, we regarded real movements of the intestine observed in the images as the changes of luminal movement, and analyzed them. We trimmed the luminal edge, counted pixels in the lumen and the low brightness area (LBA), of all VCE images and compared them between the groups. RESULTS: There was no difference in the frequency observed in the LBA corresponding to the luminal area between the groups. As for the average volume of the LBA found in an image, it was 1702 pixels in healthy persons versus 305 in IBS patients (P = 0.21) and in healthy persons it tends to be larger. We drew a graph of LBA by time-course. A periodic change in the volume of LBA was found in eight of nine (88.9%) healthy persons over time, but in only two of five (40.0%) IBS patients (P = 0.62). Using endoscopy, a difference in the bowel movement between groups A and B could be evaluated objectively. CONCLUSION: The present study presents the possibility of a new technique to evaluate functional bowel disorders objectively using an endoscopic procedure.