Programmable self-assembly of polymer nanoparticles with surface topography into functional, porous 2D/3D nanoparticle lattices

• Applicant: Professor Dr. André Gröschel
• Subject Area: Preparatory and Physical Chemistry of Polymers ; Experimental and Theoretical Physics of Polymers
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 376920678

Many current needs of science and technology can be traced back to fundamental challenges in controlling the structure and chemistry of interfaces on the micro-, meso- and nanoscale. New concepts are in demand for the development of functional materials with defined interfaces and reduced transport pathways, e.g., for the structuring of novel cathode materials for high-performance batteries, porous scaffolds for enhanced energy conversion (catalysis, photovoltaic), water purification, hybrid nanomaterials for tissue engineering, and for the miniaturization of electronic devices. One promising strategy to tackle these challenges is the self-assembly of building blocks into ordered structures from the bottom-up allowing-in principle-the positioning of multiple components with high precision and user-defined complexity. Despite much effort, the controlled self-assembly of defined porous lattices in the range of 50-500nm remains a grand challenge. This knowledge gap originates from lack of proper nanoscale building blocks with sufficiently low dispersity and the required high resolution of directional interaction patterns. Closely related is the limited understanding of self-assembly pathways and kinetics for the long-range ordering of non-close-packed nanoparticle lattices. The deformability and dynamic nature of polymer particles (as compared to hard colloids) could be the key facilitating formation of defect-free equilibrium structures. This Emmy Noether project aims at bringing together concepts of block copolymer self-assembly, and supramolecular and supracolloidal chemistry to create porous functional nano-materials. Two main challenges are addressed: the predictive formation of polymer nanoparticles with geometric surface topography and their enhanced directional self-assembly into functional open nanoparticle lattices. Specially designed block copolymers with cleavable blocks allow the combinatorial synthesis of polymer nanoparticles with accessible topography (surface beads or core cavities). We will quantify these surface features with advanced analytic tools such as cryogenic transmission electron tomography. The geometry of nanoparticles with surface beads controls the periodicity and symmetry of the formed nanoparticle lattices. Nanoparticles with core cavities are suited for lock & key co-assembly with fitting nanoparticles (organic, inorganic, biological) for highest directionality and complexity. To improve our understanding of nanoparticle assembly, kinetics will be followed online with liquid cell TEM, an emerging technique to monitor processes in-operando. Synthesis and understanding will be combined to approach the ultimate goal, the self-assembly of open nanoparticle lattices. These structures still pose a formidable experimental challenge, but are expected to offer novel properties, e.g. the diamond cubic lattice for photonic application, and stimulate new applications and theoretical considerations.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: Flüssigzelle für Transmissionselektronenmikroskopie ; Gelpermeationschromatographie-System
• Instrumentation Group: 1350 Flüssigkeits-Chromatographen (außer Aminosäureanalysatoren 317), Ionenaustauscher ; 5140 Hilfsgeräte und Zubehör für Elektronenmikroskope