Nanostructured and oriented metal-organic framework films enabling extreme surface wetting properties

Andre Mähringer; Julian M Rotter; Dana D Medina

doi:10.3762/bjnano.10.196

Nanostructured and oriented metal-organic framework films enabling extreme surface wetting properties

Beilstein J Nanotechnol. 2019 Oct 9:10:1994-2003. doi: 10.3762/bjnano.10.196. eCollection 2019.

Authors

Andre Mähringer^{1

2}, Julian M Rotter^{1

2}, Dana D Medina^{1

2}

Affiliations

¹ Department of Chemistry, Ludwig-Maximilians-Universität (LMU), Butenandtstr. 11, 81377 Munich, Germany.
² Nanosystems Initiative Munich (NIM) and Center for NanoScience (CeNS), Schellingstr. 4, 80799 Munich, Germany.

Abstract

We report on the synthesis of highly oriented and nanostructured metal-organic framework (MOF) films featuring extreme surface wetting properties. The Ni- and Co- derivatives of the metal-catecholate series (M-CAT-1) were synthesized as highly crystalline bulk materials and thin films. Oriented pillar-like nanostructured M-CAT-1 films exhibiting pronounced needle-like morphology on gold substrates were established by incorporating a crystallization promoter into the film synthesis. These nanostructured M-CAT-1 MOF films feature extreme wetting phenomena, specifically superhydrophilic and underwater superoleophobic properties with water and underwater oil-contact angles of 0° and up to 174°, respectively. The self-cleaning capability of the nanostructured, needle-like M-CAT-1 films was illustrated by measuring time-dependent oil droplet rolling-off a tilted surface. The deposition of the nanostructured Ni-CAT-1 film on a large glass substrate allowed for the realization of an efficient, transparent, antifog coating, enabling a clear view even at extreme temperature gaps up to ≈120 °C. This work illustrates the strong link between MOF film morphology and surface properties based on these framework materials.

Keywords: antifog; antifouling; biomimetic coatings; metal–organic frameworks (MOFs); superhydrophilic; superoleophobic; thin films; vapor-assisted conversion.