Welcome to the digital home of the Knebel Group. We are a multidisciplinary team working on fundamental molecular design, physicochemical characterizations and technical, industry relevant application. We are pushing the boundaries of how porous materials can solve the most pressing challenges in energy relevant climate change mitigation and resource efficient separations, and environmental pollution sensing. By stimuli responses we try to mimic the biological membrane in a technical abstraction, using light-switching, thermal glass transition, breathing phenomena and electric field-controlled distortion to create controllable pore channels. We then use these phenomena to scale materials and methods up and transfer them into mostly CO₂-related application cases.

I. Inorganic Materials Chemistry: Pore Design in Reticular Materials with Stimuli Response

At the heart of our research is reticular chemistry. We don’t just find materials; we build them from the ground up. By using metal ions and organic linkers, we assemble highly ordered, porous coordination materials, namely and foremost Metal-Organic Frameworks (MOFs), but we are also interested in crystalline polymeric frameworks: Covalent Organic Frameworks (COFs).

Our idea is to make external stimuli responsive MOFs and COFs for the desired task: Building designer materials by controlling the size, shape, and chemical environment of pores to target specific molecules. Moving beyond bulk powders, we specialize in nanosized powders, polymer composites and the growth of oriented thin films and 2D membranes through wet chemistry. Surface functionalization helps us to discover new material classes, such as “liquids with permanent porosity”, or make highly performant polymer-composite fillers through cross-linking between crystal and polymer matrix.

 

II. Physical Chemistry: Gain Fundamental Understand of the Stimuli Responsiveness in Reticular Materials

Synthesizing a material is only half the challenge: our goals is to gain a deeper understanding of the behaviour of guest molecules, ions and functional moieties within the porous architectures. This is where fundamental phenomena are characterized using in situ methods. We employ advanced spectroscopic and analytical techniques to study the thermodynamics and kinetics of interfaces.

With physciochemical methods we investigate the kinetics of diffusion in stimuli responsive reticular materials: our smart designer materials change their structure or properties in response to external physical triggers. We use a plethora of different characterization methods, from microscopy to spectroscopy to track changes in-situ. We investigate processes under operating conditions to watch and decipher the changes to the porosity structure.

III. Material Science and Technical Chemistry

Research is only as good as its impact. As a crucial part of our research, we translate molecular insights and phenomena into a scalable materials platforms for real-world applications. With membranes, we can investigate gas sensing, light-matter interactions, as well as chemical separations. Our “artificial” membranes are used to develop advanced separation processes with controllable molecular sieving ability. Stimuli responsive features are used to gain material sided control over a technical proces, or to detect analytes with high precision and sensitivity.

With synthetic upscale of reticular materials, the use of 3D-printing and experiments for machine learning we develop a scalable platform: Mixed-Matrix Membranes (MMMs) incorporate custom-designed MOFs in custom-designed polymer matrices. With membrane separation processes in Wicke-Kallenbach geometry, we investigate how MOF-membrane thin films help us to decarbonize the chemical industry and capture CO₂ from the industry fumes. Polycrystalline and glassy reticular materials help to develop separation and sensing technology of tomorrow. Improving membranes to break the upper bound of permeability and selectivity and replace energy intensive processes disruptively with novel materials in the chemical industry is our goal.

 

We recieve funding from:

Breakthroughs

 

SPP 1928/2

 

GRK 3014 PhInt

 

2022FGR 0040 (MMMs) & 2025FGR 0089 (RespoBrane)