Glued Langmuir−Blodgett Bilayers from Porous versus Nonporous Surfactants

Abstract

Poly(4-styrenesulfonate) (PSS) has been used to ionically cross-link (glue together) single Langmuir-Blodgett bilayers derived from 1,2,4,5-tetrakis[N,N-dimethyl-N-(1-hexadecyl)-ammoniummethyl]benzene (2a) and tris(N,N-dimethyl-N-hexadecylammoniummethyl)mesitylene (3). The resulting films are of high quality as judged by He/N2 permeation selectivities of ca. 100. Such selectivity is well in excess of the Knudsen diffusion limit of 2.6 and approaches that which has been found for glued bilayers of 5,11,17,23,29,35-hexakis[(N,N,N-trimethylamonium)-N-methyl-37,38,39,40,41,42-hexakis-n-hexamedecyloxy-calix[6]arene hexachloride (1). The significance of these findings to LB technology, in general, is briefly discussed.

Investigation of layer-by-layer assembled heparin and chitosan multilayer films via electrochemical spectroscopy

“…The working electrode was the polymer layered platinum electrode. Na 2 SO 4 (0.1 M) was used as supporting electrolyte, and 2.5 mM K 3 [Fe(CN) 6 ]/K 4 [Fe(CN) 6 ] (1:1) was employed as redox probe. Nitrogen was purged in the solution for 15 min before starting measurement.…”

“…The charge-transfer resistance is a character of the electron exchange between the electrode and the redox couple of K 3 [Fe(CN) 6 ]/K 4 [Fe(CN) 6 ] in solution, which depends on the interfacial structure of the electrode/electrolyte solution (Fig. 9).…”

“…6. 6 ] in solution transfer across the interface, i.e. the electric double layer, and exchange electrons on the electrode (Fig.…”

“…Compared with other molecularly controlled methods such as self-assembly monolayers (SAMs) [4,5] and Langmuir-Blodgett deposition [6], LbL assembly is more simple and has few restrictions on the substrates, therefore it is suitable to a variety of shapes of substrates [7,8]. Because of advantages mentioned above, LbL techniques are widely applied from optical materials [9][10][11][12] to biomaterials [13][14][15][16][17][18][19], filtration [20], and self-cleaning surfaces [21].…”

Challenges and breakthroughs in recent research on self-assembly

“…This tiling strategy provides a versatile design of patterns upon appropriate selection of component molecules. A unique fabrication technique for LB films in the out-plane direction was recently developed by Regen and coworkers, and is known as the 'glued LB film' [732][733][734]. They developed glued LB films through polyanion bridging of cationic amphiphiles at an LB interlayer and investigated gas permeability through the glued LB films (figure 90).…”