We have developed a new class of synthetic membranes that consist of a porous polymeric support that contains an ensemble of gold nanotubules that span the complete thickness of the support membrane. The support is a commercially available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubules are prepared via electroless deposition of Au onto the pore walls; i.e., the pores acts as templates for the nanotubules. We have shown that by controlling the Au deposition time, Au nanotubules that have effective inside diameters of molecular dimensions (<1 nm) can be prepared. Hence, these membranes are a new class of molecular sieves. In addition, because these membranes are composed of an electronically conductive material, excess charge can be applied to the tubules by electrochemical charging in an electrolyte solution. We have shown that this allows for control of ion-transport selectivity in these membranes. Finally, because the tubules are composed of gold, well-known Au-thiol chemistry can be used to change the chemical environment within the tubules. Via this route chemical transport selectivity can be introduced into these membranes. This paper reviews progress on size-based, charge-based, and chemical-interaction-based transport selectivity in this new class of membranes.

We have developed a new class of synthetic membranes that consist of a porous polymeric support. This support contains an ensemble of gold nanotubules that span the complete thickness of the support membrane. The support is a commercially available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubules are prepared via electroless deposition of Au onto the pore walls, and tubules that have inside diameters of molecular dimensions (<1 nm) can be prepared. Hence, these membranes are a new class of molecular sieves. We review in this paper the ion‐transport properties of these Au nanotubule membranes. We will show that these membranes can be cation‐permselective or anion‐permselective, and that the permselectivity can be reversibly switched between these two states. Ion permselectivity can be introduced by two different routes. The first entails chemisorption of an ionizable thiol, e.g., a carboxylated or ammonium‐containing thiol to the Au tubule walls. If the thiol contains both of these functionalities (e.g., the amino acid cysteine), the permselectivity can be reversibly switched by varying the pH of the contacting solution phase. Ion permselectivity can also be introduced by potentiostatically charging the membrane in an electrolyte solution. By applying excess negative charge, cation permselective membranes are obtained, and excess positive charge yields anion permselective membranes. In this case the permselectivity can be reversibly switched by changing the potential applied to the membrane.

A series of efficient and bright white light-emitting diodes were fabricated using the blends of two fluorene-derived fluorescent dyes, (4,7-bis-(9,9,9′,9′-tetrahexyl-9H,9′H-[2,2′]bifluoren-7-yl)-benzo[1,2,5]thiadiazole) (FFBFF-emits green) and (4,7-bis-[5-(9,9-dihexyl-9H-fluoren-2-yl)-thiophen-2-yl]-benzo[1,2,5]thiadiazole) (FTBTF-emits red) in an efficient blue-emitting polyfluorene-derived copolymer (poly[(9,9-bis(4-di(4-n-butylphenyl)aminophenyl))]-stat-(9,9-bis(4-(5-(4-tert-butylphenyl)-2-oxadiazolyl)-phenyl))-stat-(9,9-di-n-octyl)fluorene) (PF-TPA-OXD). The resulting white light-emitting device reaches a maximum external quantum efficiency of 0.82% and a maximum brightness of 12900cd∕m2 at 12V. The Commission Internationale d’Énclairage chromaticity coordinates of the device remain very close to that of pure white emission at a relatively broad bias range from 6V(x=0.36,y=0.37)to12V(x=0.34,y=0.34).