SPP 2171 Spring Conference: Dynamic Wetting of Flexible, Adaptive, and Switchable Substrates

Nanopores are a key component in various technologies from oil production, separation and sensing, to drug delivery or catalysis and energy conversion. In contrast to technological pores, biological pores and channels demonstrate highly precise transport being directed, highly selective, and gated. A key factor to this performance is their nanoscale structure and local control on charge regulation and polarity. Inspired by this performance and nanoscale precision we are interested in designing precisely functionalized nanoscale porous materials to understand and advance transport performance of technological pores.[1]
This talk will highlight the role of nanopore wettability regarding fluid imbibition,[2] and molecular transport.[3] Strategies to adjust nanopore wettability of mesoporous silica films and with this ionic transport will be presented, for example, using gas phase deposition of fluorinated silanes, spiropyran as a photoresponsive molecule[4]. The gained knowledge on wettability in nanopores was used to apply adjusted wettability transitions together with orthogonal surface chemistry to locally place three different functions or polymers into a nanopore[5] or to use wettability transition design to gate water imbibition and droplet coalescence by light.[4] Looking at more complex hierarchical materials dense and mesoporous silica coatings can be introduced into paper to design paper wettability and with this prevent or accelerate fluid transport in this very hierarchical material even with three dimensional control. Mechanistic insights into this design of paper properties as obtained by high resolution microscopy will be given.[6, 7]

1. R. Pardehkhorram, A. Andrieu-Brunsen, Chem. Commun., 2022, DOI: 10.1039/D2CC01164F
2. A. Khalil, F. Schäfer, N. Postulka, M. Stanzel, M. Biesalski, A. Andrieu-Brunsen, Wettability-defined
   droplet imbibition in ceramic mesopores, Nanoscale, 2020, 12, 24228.
3. A. Khalil, M. Zimmermann, A. K. Bell, U. Kunz, S. Hardt, H.-J. Kleebe, R. W. Stark, P. Stephan, A. Andrieu-
   Brunsen, “Insights into the interplay of wetting and transport in mesoporous silica films“, J. Colloid Interf. Sci.,
   560, 369, (2019).
4. A. Khalil, P. Rostami, G.K. Auernhammer, A. Andrieu-Brunsen, Mesoporous Coatings with Simultaneous
   Light-Triggered Transition of Water Imbibition and Droplet Coalescence, Adv. Mater. Interfaces, 2021, 8,
   2100252.
5. M. Ochs, R. Mohammadi, N. Vogel, A. Andrieu-Brunsen, „Wetting-controlled localized placement of
   surface functionalities within nanopores“, Small, 2020, 16, 1906463
6. M. Nau & N. Herzog, J. Schmidt, T. Meckel, A. Andrieu-Brunsen & M. Biesalski, Janus‐Type Hybrid Paper
   Membranes, Adv. Mater. Interf., 2019, 6, 1900892.
7. J. J. Mikolei, M. Biesalski, M. Ceolin, A. Andrieu-Brunsen, Local water management in cotton linter papers with
   silica-based coatings, Cellulose, 2024, 31, 5855.