Vapor Phase Deposition of Porous Polymer Dendrites

The synthesis of hierarchical structures with different length scales is useful for designing self-cleaning surfaces, adhesives, templates for catalysis, and sensors. In this work, we study the formation of three-dimensional porous poly(methacrylic acid) dendritic structures using vapor phase deposition. These polymer dendrites have a hierarchical structure composed of branched finger-like features with small scale pores inside these features. These structures are prepared by limiting the concentration of methacrylic acid monomer introduced into the reactor, which results in diffusion-controlled nucleation and growth on the substrate. The nucleation of the dendritic structures can be controlled through changes in the surface energy of the substrate. For example, physical defects can be used to enhance nucleation and manipulate the location of dendrite growth and the use of a low surface energy coating can be used to limit nucleation. The coverage on the substrate and the thickness of the dendrites can be systematically tuned by varying processing parameters. The results of this study provide a one-step solventless synthesis process for fabricating polymer materials that can be used to build next-generation surfaces and templates.