Ordered Arrangement of Micro-beads in Single Line by Micromolding in Capillaries

An effective procedure was demonstrated to arrange spherical micro-beads into ordered, long, line-shape arrays by means of "micromolding in capillaries" in soft lithography. Polystyrene (PS) micro-beads with 2-3 mm of diameter were used as units and arranged by molding in continuous micro-channels formed by the conformal contact between a glass substrate and an elastomeric stamp with micrometer-scale line patterns on the surface. An aqueous emulsion of PS micro-beads filled these channels by capillary action and was allowed to solidify. The stamp was then removed. The PS micro-beads could be assembled into a string of long line-shape arrays, and the strings were then joined by heating them to their softening temperature.In order to separate the PS micro-bead string from the substrate, the glass was covered with a thin layer of Al or polymethyl methacrylate. After the Al layer was dissolved, the string of PS micro-beads would be released. A string of micrometer scale PS beads can be used as a simple and direct "model" of a real macromolecular chain. It is hopeful to show an analogue with the condensed process of real macromolecules in a mesoscopic scale using the "string of PS micro-beads".