Confinement-Induced Growth of Gold Nanocrystals in Hybrid Hierarchical Polymer Nanowire

Abstract

The growth of metal nanocrystals within polymer nanowires deviates from the conventional nucleation-growth process as movements of nucleated metal nanocrystals are hindered due to simultaneous growth of the polymer. We have carried out systematic in situ small-angle and diffraction measurements simultaneously during growth of gold-polypyrrole composite nanowire within membranes and developed a method to extract the shape and size of gold nanocrystals to understand the growth mechanism. Our results give unique information regarding the early growth processes of nanocrystals as a function of the pore diameter of membranes and concentration of HAuCl 4 solution used for the polymerization reaction. We have shown that gold nanocrystals first grow along the [111] direction through contact epitaxy as a cylindrically shaped nanocrystal and then get transformed into nearspherical nanocrystals. The synchrotron X-ray scattering technique presented here can be used to study similar growth processes.

Ordering of ZnS Nanorods at the Air–Liquid Interface: An In Situ X-ray Scattering Study

“…of position vectors of the nanorods {r⃗ n }. 42 The correlation function for this type of paracrystal 43 can be written as where (r⃗ i = (x i ,y i ,z i )) is the mean position of the ith particle and σ ix , σ iy , and σ iz are the standard deviation about the mean position along x-, y-, and z-direction of the i-th nanorod with σ σ = n n where n is the ratio of the position of the n-th particle to the average separation. The corresponding interference function can be obtained by using Fourier transform to the correlation function C(r⃗ ) as given by…”

“…We have generated the whole lattice by repeating this set along the x -direction by the translational vector {2 L , 0, 0} and along y -direction by the translational vector {0, a , 0}. In this way, we can produce a set of position vectors of the nanorods { r⃗ n } . The correlation function for this type of paracrystal can be written as where ( r⃗ i = ( x i , y i , z i )) is the mean position of the i th particle and σ ix , σ iy , and σ iz are the standard deviation about the mean position along x -, y -, and z -direction of the i -th nanorod with where n is the ratio of the position of the n -th particle to the average separation.…”