Radiation-induced synthesis of gold nanoparticles within lamellar Phases. Formation of aligned colloidal gold by radiolysis

A sheared lamellar phase has been used as a nanoreactor for the synthesis of gold nanoparticles by radiolysis and by a photochemical approach. A gold salt solution (KAuCl4, 10-2 M) is introduced into the aqueous compartments between the lipid-based bilayers. Gold nanoparticles grow within the lamellar phase as shown by TEM analysis and X-ray diffraction, limiting the particle size. Homodisperse, 2.4- and 5.9-nm-sized, spherical nanoparticles are produced by irradiation and UV irradiation, respectively. When produced by radiolysis, they are perfectly aligned along the lamellae. Their UV-vis spectra display a maximum at 565 nm suggesting that nanoparticles are coupled by dipole-dipole interactions within the lamellar phase