A simple method go produce dendrimer nanodots over centimeter scales by rapid evaporation of solvents

A simple method to produce aggregates of dendrimers in a form of nanometer- sized round dots over an area measured in centimeters is presented. The met hod is based on rapid evaporation of a solvent from a thin cast film of an electrolyte solution of polyamidoamine dendrimers on mice. Chemically speci fic adsorption, electrostatic interactions, phase transitions, and dewettin g instabilities are shown not to be responsible for the dot formation. Chan ges in temperature and humidity have only little effect. There is a thresho ld evaporation rate above which the dots are formed. Once formed, the dot s ize and spacing are independent of the evaporation rate. The dot is also fo rmed by different types of dendrimers and solutes, demonstrating the wide a pplicability of the present method.