Polysiloxane Nanotubes

Abstract

The synthesis of polysiloxane nanotubes using trifunctional organosilanes is reported. Tubular nanostructures were formed via a chemical vapor deposition technique at room temperature when ethyltrichlorosilane is used or via a liquid phase method when methyltriethoxysilane is used as precursor. In the chemical vapor deposition process the shape of the tubes was controlled by changing the water content in the reaction chamber prior to coating. The diameter varied between 60 and 4000 nm. While in the case of the liquid phase method nanotubes with very high aspect ratios of 800 are produced. Parameters, such as length and diameter of the various tubes, were investigated using scanning electron microscopy and transmission electron microscopy. Additionally, the chemical composition of produced structures was analyzed using attenuated total reflectance-infrared and energy-dispersive X-ray spectroscopy. Glass substrates coated with such structures exhibit extreme superhydrophobic properties.

Hollow polysiloxane nanostructures based on pressure-induced film expansion

“…The presented nanostructures are synthesized similarly to previously reported solid SNFs, [12][13][14][15][16][17][18][19][20][21][22][23][24][25] and under scanning electron microscope (SEM), they appear exactly similar, yet detailed transmission electron microscope (TEM) analysis reveals them to exhibit a hollow core. The h-SNFs also differ from the previously reported polysiloxane nanotubes 26 in that h-SNFs are topographically similar to solid SNFs, while the nanotubes exhibit a different morphology. Our model is based on (a) chemical condensation reactions occurring inside a partially cross-linked polysiloxane film, which release gaseous by-products, and (b) concomitant physical effects, which enable uniaxial elongation.…”

“…A cross-sectional profile over a single h-SNF reveals the hollow core most clearly and also shows that the diameter of the h-SNF is comparable to the diameter of SNFs. The diameter of the structures is only a fraction of the hollow polysiloxane structures reported previously, 26 wherein the structure diameters were in excess of 60 nm.…”

“…9 In 2006-2007, three groups independently reported on the first successful synthesis of the 1D polysiloxane nanostructures [14][15][16] and later more studies emerged to deepen the understanding of the process parameters, 12,13,[17][18][19][20][21][22][23][24][25] and recently, also larger tubular polysiloxane structures were introduced. 26 A few growth models for the SNFs have been proposed until this day. [18][19][20]24,27,28 However, these models are challenged by our observation of hollow polysiloxane nanostructures.…”

One-dimensional silicone nanofilaments

“…Coated substrate materials include fabrics made of cotton [8,13,14,30,55], wool [8,14], silk [14], viscose [14], cellulose acetate [14], polyacrylnitrile [14], polyester [14,40], Kevlar® [22], wood [8], polyethylene [8], silicone [8], ceramics [8], glass [8,11,12,18,19,24,28,29,35,36,41,43,56,57], quartz or silica [16,57], silicon [7-10, 12, 16, 42, 58-62], germanium [16], titanium [8,9] and aluminium [8,16,63] (figure 1). …”

“…This is performed in solvents, alkaline or cleansing solutions with or without ultrasonication [8,11,13,16,18,24,41,43,56,63], activation in a plasma using oxygen [7-10, 16, 36, 57, 59] or a mixture of oxygen and hydrogen as process gas [60][61][62], treatment in strongly oxidising liquids such as a piranha solution [16,28,29], ozone in combination with UV-light [64], or combinations of these methods [12,[60][61][62]64]. Fabrics may be subjected to a specific procedure [30].…”