1 Particle design and formulation for hierarchical materials Wolfgang Peukert Institute of Particle Technology Cluster of Excellence – Engineering of Advanced Materials www.lfg.fau.de, www.eam.fau.de 150 years BASF Smart energy for a sustainable future
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Particle design and formulation for hierarchical materials
Wolfgang PeukertInstitute of Particle Technology
Cluster of Excellence – Engineering of Advanced Materialswww.lfg.fau.de, www.eam.fau.de
150 years BASFSmart energy for a sustainable future
Outline
Concepts of product design and materials assembly
Towards rigorous mathematical optimization
Particle Formation
• Modelling of gas phase synthesis
• Optimization of time – temperature profiles
• Modelling of quantum dot synthesis
• FIMOR: a fully implicit method for Ostwaldt ripening
Aspects of formulation science and technology
Hierarchies: self-assembly and thin films
Conclusions
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Structure – property functions across all levels:Molecular, particulate, particle ensemble, final product
Product design
Process – structure functionsProcess design and process variables determine structure formation ofmolecules, particles, particle ensembles and final product.
Process chain, e.g. for semiconductor formation/application
SynthesisPhase A
Phase transferPhase B Formulation Thin film
High surface area &low pressure drop & catalytic
Transparent & smooth & very strong
Free flowing & easily dispersible& controlled defect state
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Property functions
Property function = f (dispersity, composition)Dispersity: Size, shape, structure, surface
Objectives:Develop colloidal process engineering including• understanding of formation mechanisms• stabilization and chemical modification• purification and classification• process modelling• continuous scalable production• modelling of formation dynamics• integration into devices
Objectives Continuous, highly reproducible particle production Transfer from batch reactions Investigation of growth mechanism & kinetics Optimization of process parameters Development of new reactors & processes
Process conditions & challenges Continuous micro-reaction setup Several feed lines Wide temperature and pressure range Flow rates from 100 ml/h to 4 l/h, In-situ optical characterization Advanced process control
ΔG = -50 kJ ∙ mol-1 for Au-SΔG = -30 kJ ∙ mol-1 for CdSe-S
Binding strength ITC, (here: ZnO / catechol)
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Self-organization of particles
Particles with „molecular“ complexityComplex superstructures@new propertiesPhase behaviourMechanisms and kinetics of formation
Glotzer et al, Nature 2007
Library of building blocks andtheir organization principles
1 µm
300 nm100 nm
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Zn(CH3COO)2 *2H2O
initiation in block copolymer melt,sonication in water
Complexation of Zn(CH3COO)2 within the polymer matrix at 150 °C in the melt.
ZnO superstructures in polymer melt
Jeffamine block copolymer
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Consecutive oriented, multiple aggregation process
ZnO ellopsoid formation mechanism
Klaumünzer et al, Cryst.Comm.Eng. 2014
Temporal evolution of UV/VIS spectra
5 min
10 min
15 min
20 min
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Define• Identification of
desirable optical properties
Design• Forward simulation• Shape and topology
optimization
Build• “Toolkit“ for
nanostructured particle synthesis
Test• Single and
multiple particle optical characterization
Ext
inct
ion
Wavelength
Product design of optical materials
Design of transparent UV absorbers
Nanoscale 2012
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One perspective: Optical properties …
…. strongly depend on size, shape, core-shell properties, topology and materials
Colloidal crystals (N. Vogel) Patchy particles (R. Klupp Taylor)
Shape optimization (G. Leugering): Making particles invisible
Functional thin films
Relevance of layered systems, e.g.
• Electrodes, e.g. fuel cells, electrolysis, batteries• Printable electronics, e.g. displays, LEDs• Membranes• Solar absorber & solar cells• Supercaps• Thermoelectrical devices• Heat management• Catalyst layers• …..
TEM Tomography, E. Spiecker, Erlangen
SAM@pressure Ordered C60-SAM monolayerSAM@FET
Key questions: Understanding and tailoring structure-property and process-structure functions Layered systems and their interactions (adhesion, transfer across interfaces) Continuous role-to-roll production
Particleformation
Gas phase synthesisHydrothermal synthesisPrecipitation…..
Process chain for printed thin films
200 nm
200 nm
200 nm
Functionalisation& Spectroscopy
fs spectroscopyESR, PL, IS, HRTEM
Sn doped In2O3 K
Ene
rgy
Undoped In2O3
StabilizationLayer formation
Chemical modificationSpin-/dip-coatingµ-contact printing….