Metal-phenolic coordination complexes, which have tunable physicochemical and biological properties, are an emerging coating material useful on various substrates. Metal-phenolic nanopatterns (MPnPs) would be useful in many applications, but few methods exist for modifying substrates with these crosslinked macromolecular networks. In this talk, I will introduce a general nanopatterning strategy that takes advantage of the dynamic coordination bonds between polyphenols and metal ions (e.g., Fe³⁺, Cu²⁺) to create structures on surfaces with a range of properties. With this methodology, under acidic conditions, 29 metal-phenolic complex-based precursors composed of different polyphenols and metal ions are patterned using scanning probe and large area cantilever free nanolithography techniques, resulting in a library of deposited metal-phenolic nanopatterns. Significantly, post-treatment of the patterns under basic conditions (i.e., ammonia vapor) triggers a change in coordination state and results in the in situ generation of more stable macromolecular networks firmly attached to the underlying substrates. The methodology provides control over feature size, shape, and composition, almost regardless of substrate (e.g., Si, Au, silicon nitride). Under reducing conditions (i.e., H₂) at elevated temperatures (180-600 °C), the patterned features have been used as nanoreactors to synthesize individual metal nanoparticles. At room temperature, the ammonia-treated features can reduce Ag⁺ to form metal nanostructures, and be modified with peptides, proteins, and thiolated DNA via Michael addition and/or Schiff base reaction. The generality of this technique should make it useful for a wide variety of researchers interested in modifying surfaces for catalytic, chemical and biological sensing, and template-directed assembly purposes.

Chaojian Chen

Appearances