Abstract

Superhydrophobic surface has been successfully prepared on cotton substrates with inexpensive and ordinary raw materials, Al(NO₃)₃ and sodium stearate (C₁₇H₃₅COONa). Such surfaces were obtained first by dip-coating the nano-Al sol, then the surface of the Al coating was modified with sodium stearate, to gain a thin film through self-assembly. The wettability of treated fabrics was characterized by water contact angle, spray test and hydrostatic pressure test. The results showed that the cotton fabrics treated with 1.5% Al sol and 20 mmol/L sodium stearate showed excellent hydrophobic properties and UV protection efficiency, water contact angle could reach 146.27° and the UPF value was 164.06 (UPF rating 50+). The morphology and surface roughness were characterized by SEM and AFM. The interaction between sodium stearate and Al coating was elucidated by XPS.

Abstract

Abstract

Durable superhydrophobic cellulose fabric was prepared from water glass and n-octadecyltriethoxysilane (ODTES) with 3-glycidyloxypropyltrimethoxysilane (GPTMS) as crosslinker by sol–gel method. The result showed that the addition of GPTMS could result in a better fixation of silica coating from water glass on cellulose fabric. The silanization of hydrolyzed ODTES at different temperatures and times was studied and optimized. The results showed that silanization time was more important than temperature in forming durable hydrophobic surface. The durability of superhydrophobicity treatment was analyzed by XPS. As a result, the superhydrophobic cotton treated under the optimal condition still remained hydrophobic properties after 50 washing cycles.

Abstract

Superhydrophobic surfaces have been successfully prepared by sol–gel method using water glass as starting material. Such surfaces were obtained first by dip-coating the silica hydrosols prepared via hydrolysis and condensation of water glass onto cotton substrates, then the surface of the silica coating was modified with a non-fluoro compound, hexadecyltrimethoxysilane (HDTMS), to gain a thin film through self-assembly, superhydrophobicity with a water contact angle higher than 151° can be achieved. The morphology and surface roughness were characterized by SEM and AFM.

Tetrabutyl titanate was used as sol–gel precursor of a nanosized TiO₂ coating to improve the photo-stability of aramid fibers. The nanosized TiO₂ coating was characterized by XRD and XPS. The influence of the TiO₂ coating on photo-stability of aramid fibers was investigated by an accelerated photo-ageing method. The photo-stability of aramid fiber showed obvious improvement after coating. After 156 h of UV exposure, the coated fibers showed less deterioration in mechanical properties with the retained tensile strength and elongation at break greater than 36 and 50% of the original values, respectively, whereas the uncoated fibers degraded completely and became powdery. SEM analysis showed no significant surface morphological change on the coated fiber after the exposure, while some latitudinal crack fractures appeared on the uncoated aramid fiber. The effect of the nanosized TiO₂ coating was also well demonstrated by examining the difference of distributions of C1s in XPS deconvolution analysis on the surface of uncoated/coated fibers with increasing UV exposure time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3113–3119, 2007

A new family of functionalized calix[4]arenes has been synthesized from calix[4]arene or azo-calix[4]arene by acylation with the corresponding ω-alkylmercapto acid chloride. Six new compounds 4a–4c and 5a–5c were isolated and characterised by MALDI, elemental analyses, ¹H NMR and ¹³C NMR. NMR spectral data showed that these azo-functionalized calix[4]arenes 5a–5c are all in 1,3-alternate conformation in solution at room temperature while calix[4]arenes 4a–4c are all in cone conformation. The IR and UV properties of calix[4]arenes 5a–5c were also investigated.