Micellar Nanoreactors-Preparation and Characterization of Hexagonally Ordered Arrays of Metallic Nanodots

The preparation of hexagonally ordered metallic nanodots was studied in detail with emphasis on the chemical state of the resulting particles. To obtain these dots, in a first step micellar structures were formed from diblock copolymers in solution. The reverse micelles themselves are capable of ligating defined amounts of a metal salt within their cores, acting as nanoreactors. After transfer of the metal‐loaded reverse micelles onto a substrate, the polymer was removed by means of different plasmas (oxygen and/or hydrogen), which also allow the metal salt to be reduced to the metallic state. In this way, ordered arrays of metallic nanodots can be prepared on various substrates. By adjusting the appropriate parameters, the separation and the size of the dots can be varied and controlled. To determine their purity, chemical state, and surface cleanliness—all of which are crucial for subsequent experiments since nanoscale structures are intrinsically surface dominated—in‐situ X‐ray photoelectron spectroscopy (XPS) and ex‐situ transmission electron microscopy (TEM) were applied, also giving information on the formation of the nanodots. Formation of arrays of metallic nanodots by a new, versatile, bottom‐up approach is described. Spherical reverse micelles are loaded with a metal salt and then deposited onto a smooth substrate, exploiting their self‐assembly into an ordered array. Exposure to an oxygen or hydrogen plasma is demonstrated to reduce the salt to the corresponding metal and simultaneously remove the polymer matrix without destroying the order. The Figure shows a gold nanoparticle array formed in this way.