Controlling the transport properties of gold nanotubule membranes using chemisorbed thiols

We have developed a new class of synthetic membranes that consist of a poro us polymeric support that contains an ensemble of gold nanotubules that spa n the complete thickness of the support membrane. The support is a commerci ally available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubules are prepared via electroless deposition of Au onto the pore walls; that is, the pores act as templates for the nanotubule s. We have shown that by controlling the Au deposition time, Au nanotubules that have effective inside diameters of molecular dimensions (<1 nm) can b e prepared. Hence, these membranes are a new class of molecular sieves. In addition, because the tubules are composed of gold, well-known Au-thiol che mistry can be used to change the chemical environment within the tubules. T his paper reviews recent research on using chemisorbed thiols to control th e transport properties of Au nanotubule membranes. The use of both electric al neutral thiols to introduce chemical-transport selectivity and charged t hiols to introduce ion-transport selectivity is reviewed.