title: Growth kinetics of gold nanocrystals: a combined small-angle X-ray scattering and calorimetric study.
abstract: The growth of gold nanocrystals prepared by the reduction of tetrachloroauric acid by tetrakis(hydroxymethyl)phosphonium chloride, which allows slow reduction, is investigated by small-angle X-ray scattering and isothermal titration calorimetry in combination with transmission electron microscopy. The growth of the nanocrystals does not follow the diffusion-limited Ostwald ripening but instead follows a sigmoidal rate curve. The activation energy obtained from the temperature-dependent growth study is very small. The heat change associated with the growth is determined for the first time as approximately 10 kcal mol(-1) per 1 nm increase in the nanocrystals' diameter.
authors.affiliation: Chemistry and Physics of Materials Unit, DST nanoscience unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur P. O., Bangalore 560064, India.
authors.forename: Kanishka
authors.initials: K
authors.lastname: Biswas
authors.forename: Neenu
authors.initials: N
authors.lastname: Varghese
authors.forename: Chintamani N R
authors.initials: CN
authors.lastname: Rao
mesh_terms: D002151:Calorimetry; D003460:Crystallization / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D053838:Scattering, Small Angle; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D006046:Gold