Wetting controls functionalization of nanopores

Precise placement of three different functional units accomplished

2020/03/26

Researchers at TU Darmstadt and FAU Erlangen-Nürnberg combine wetting effects and orthogonal surface chemistry for a precise placement of three functional units into nanopores.

Visualization of the second step of functionalization: By hydrophobization of the pore walls, the liquid solution containing the functional molecules is not able to enter the pores.

Biological membranes are permeable to certain substances, others will be blocked. Their complex structures are even able to regulate the transport of molecules. In the context of sensing and transport control, artificial biomimetic nanopores play a crucial role. The design of multifunctional nanopores and the precise positioning of multiple functional units such as polymer chains is challenging. Scientists from the group of professor Annette Andrieu-Brunsen (TU Darmstadt) and professor Nicolas Vogel (FAU Erlangen-Nürnberg) have demonstrated for the first time how a combination of orthogonal surface chemistry and controlled wetting states can be used to position three different functional units into nanopores.

The scientists used inverse colloidal monolayers and coated the surface and the pore bottoms with a gold layer of 20 nm thickness. The pore walls remained uncoated.

In a subsequent step the pore walls were hydophobized using the so-called SI-ROMP polymerization technique. Thus, the liquid solution containing the functional units was not able to enter the pores: It only functionalized top surface of the inverse colloidal monolayer.

By adding a solvent to another solution containing the second functional polymer, the liquid was enabled to enter the pores and functionalize their bottoms.

The scientists demonstrated their multiple functionalization by contact angle measurements, infrared spectroscopy and X-ray photoelectron spectroscopy.

The publication

Ochs, M., Mohammadi, R., Vogel, N., Andrieu‐Brunsen, A., Wetting‐Controlled Localized Placement of Surface Functionalities within Nanopores. Small 2020, 1906463. https://doi.org/10.1002/smll.201906463