Covalent Gluing and Postgluing of Langmuir−Blodgett Monolayers at Hydrocarbon Surfaces

Abstract

Langmuir-Blodgett (LB) monolayers of 5,11,17,23,29,35-hexaformyl-37,38,39,40,41,42-hexakis(1-n-octyloxy)calix[6]arene (2), deposited onto silylated silicon wafers, were cross-linked (i.e., "covalently glued") via Schiff base formation with poly(allylamine). Direct evidence for imine formation was obtained from X-ray photoelectron spectroscopy and from attenuated total reflection IR spectroscopy. These modified surfaces could be removed from the aqueous subphase into air with retention of the assembly and its orientation relative to the surface, as evidenced by atomic force microscopy, water contact angle measurements, and film thickness determinations by ellipsometry. Similar assemblies were also synthesized via a postgluing procedure, in which the substrate containing the LB monolayer was removed from the subphase and rapidly immersed into an aqueous solution containing poly(allylamine). The potential of combining postgluing methods with continuous LB film deposition as a surface modification technique is briefly discussed.

Characterization of Langmuir–Blodgett films of a calix[8]arene and sensing properties towards volatile organic vapors

“…Calix[n]arene derivatives can be deposited onto several solid substrates such as quartz crystal [51], mica [52], silicon [53], cadmium arachidate [54], silver [55] and ITO [56]. These studies showed that the deposition is strongly depend on the substrate surface.…”

A 7 nm Thick Polymeric Membrane With a H2/CO2 Selectivity of 200 That Reaches the Upper Bound

“…Experimental methods that were used to (i) synthesize 5,11,17,23,29,35hexakis[(N,N,N-trimethylamonium)-N-methyl-37,38,39,40,41,42-hexakis-nhexadecyloxy-calix[6]arene chloride (i.e., Calix), (ii) deposit Langmuir-Blodgett (LB) bilayers of PAA-crosslinked Calix, 1 and 2 onto poly[1-(trimethylsilyl)-1-propyne] (PTMSP) supports or silicon wafers (silylated with n-octadecyltrichlorosilane, OTS), (iii) quantify gas permeabilities, and (iv) measure film thicknesses by ellipsometry were similar to those that have previously been described. [1][2][3] Ellipsometry measurements were made using VASE ellipsometer (J.A. Woollam Co., Inc., Lincoln, NE), equipped with variable wavelength ( from 250-1700nm) and angle of incidence (15º-90º) system, a λ of 632.8nm and an incidence angle of 70º were chosen for measurements.…”

Amphiphile nanoarchitectonics: from basic physical chemistry to advanced applications

“…In order to demonstrate this concept, a calix [6]arene derivative was used as the bilayer-forming, water soluble, charged, amphiphile and poly(4-styrenesulfonate) (PSS) as the glue. [285][286][287] These glued bilayers are ultrathin with thicknesses of around 6 nm, although they are easy to prepare and process. They can be used as organic nanomembranes for gas separation applications since they exhibit remarkable permeation selectivity involving He, N 2 and CO 2 .…”