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1174-V11-05

Ordered Nanoparticle Arrays Synthesized from Self-Assembled Diblock Copolymer Templates Qiang Fu, Anita Ghia, Chi-shuo Chen, Jennifer Lu School of Engineering, University of California, Merced Merced CA95348 ABSTRACT We present a comprehensive study of using diblock copolymer micelle templates to synthesize ordered nanoparticle arrays. Ionic and coordination bonds have been exploited to incorporate nanoparticle precursors into cores of block copolymer micelles. Polystyrene-b-poly (4-vinylpyridine) (PS-b-P4VP) has been shown to be able to localize anions via electrostatic attraction with protonated pyridine cations while transitional metals can be sequestered through coordination bonds. Polystyrene-b-poly (acrylic acid) (PS-PAA) can localize a variety of cations via ionic bonds with acrylic anions. We have demonstrated that the size of nanoparticles can be tuned by controlling the solution concentration of an ionic precursor. By mixing these two distinct block copolymers which can selectively interact with different precursor species, complex nanoparticle architectures can be generated thus paving a path for new applications. 1. INTRODUCTION There have been burgeoning research efforts aiming for establishing controllable nanoparticle synthesis due to their technological potential in catalysis, sensing, medicine and electronic and optoelectronics [1-4]. Many of these applications require nanoparticles with controllable size, compositions, spacing and location. In the past decade, biological templates and synthetic templates [5-6] have been explored to generate nanoscale morphologies. Among them, templating self-assembled block copolymers has emerged as one of the most promising approaches for nanoparticle formation because of its simplicity, versatility and low cost. Diblock copolymers are polymers with two different polymer blocks connected by a single covalent bond. In selective surroundings such as a solvent preferential for one block, diblock copolymers will phase separate into various morphologies [7]. For example, hexagonal micelles formed by self-assembly of diblock copolymers in solution followed by coating into monolayer films have been used to localize nanoparticle precursors to form ordered nanoparticle arrays on substrates [8]. The size and spacing of nanoparticles can be controlled by adjusting the block length and loading ratio of metal precursors [9-10]. In addition, diblock copolymers are compatible with standard semiconductor fabrication processes and can be readily implemented in microelectronic and optical device fabrication. Essential to the employment of diblock copolymer templates for nanoparticle formation is the ability to sequester nanoparticle precursors selectively onto one of the blocks. Herein we report, by exploiting electrostatic and coordination interactions between nanoparticle precursors and functional groups of the repeat units of a diblock copolymer, a variety of new and existing types of uniform nanoparticles have been successfully generated. By utilizing two different