Int. Conference on high-throughput materials R&D, Ghent – 02-04 June High-throughput synthesis platform to enhance the development of microcapsules E. Bauters (Flamac) and S. Cakir (PCR UGent) Int. Conference on high-throughput materials R&D, Ghent – 02-04 June

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Outline Introduction Encapsulation technologies Automated synthesis of micro-capsules Characterisation of micro-capsules Case study Conclusions Int. Conference on high-throughput materials R&D, Ghent – 02-04 June

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Introduction High-throughput methods seem to be perfectly suitable for polymer research due to the fact that many parameters can be varied during polymer synthesis (e.g., monomers, catalysts, initiators, solvents and reaction conditions), processing, blending and compounding The reproducibility of the automated reactions and their comparability with conventional laboratory experiments are also important issues and need to be tested in advance Close collaboration between PCR-UGent and Flamac Int. Conference on high-throughput materials R&D, Ghent – 02-04 June

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Encapsulation technologies • Applications – Protection of unstable ingredients Vitamin C, enzymes, … Reduction of the side effect of some ingredients Organic UV filters, … Providing controlled release Perfume delivery for fabric treatment, … Using visible spheres as a marketing tool Release of active ingredients when triggered Self-healing materials, corrosion inhibitors, … www.devan.net – – – White et al., Adv. Mater. 2009, 21, 645–649 Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 4

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Encapsulation technologies • Micro-encapsulation by chemical methods – Based on polymerisation or polycondensation mechanisms Interfacial and in situ polymerisation processes gained most scientific industrial attention and – Important alternatives to coacervation Boh et al., Bioencapsulation Innovations, March 2013 Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 5

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Encapsulation technologies • Requirements for micro-capsules – Mechanical properties • Robust to survive their manufacture • Brittle to break when external trigger Thermal stability Resistance to solvents – Good shelf life to insert them into formulations or materials Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 6

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Automated synthesis of micro-capsules • Different types of micro-capsules possible Melamine- formaldehyde shell Polyurea shell Polycondensation Interfacial polymerization Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 7

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Automated synthesis of micro-capsules • Automated synthesis platform – From manual synthesis to an automated protocol Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 8

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Automated synthesis of micro-capsules • Automated synthesis platform Viscous liquid dosing unit Powder dosing unit Liquid handling & pH trimming unit High shear mixer Custom-made synthesis reactor Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 9

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Automated synthesis of micro-capsules Reliability of high-throughput synthesis platform Reproducibility of benchmark synthesis MF-microcapsules containing cyclohexane in high-throughput Batch # Reactor Pre-condensate (pH > 9) Emulsion pH = 5,5 ± 0.15 Polycondensate pH = 5,15 ± 0.15 1 9.13 5.62 5.21 2 9.09 5.64 5.33 3 9.04 5.68 5.18 4 9.07 5.57 5.09 5 9.18 5.56 5.27 6 9.11 5.58 5.28 Average 9,11 5,58 5,28 St.dev 0,05 0,09 Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 10

Reliability of high-throughput synthesis platform Particle size distribution of different batches of Cyclohexane containing MF-microcapsules Graph 1. PSD of batch # 7 Batch # Mean D (μm) Average D [v,0.1] (μm) [v,0.5] (μm) [v,0.9] (μm) 7 30,95 5,93 28,53 59,15 8 29,45 5,00 26,49 58,23 9 31,77 7,57 29,59 58,63 10 28,18 6,07 27,57 49,88 11 26,66 5,61 24,73 49,76 Average 29,40 6,04 27,38 55,13 St. Dev 2,06 0,95 1,87 4,86 Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 11

Reliability of high-throughput synthesis platform • Melamine formaldehyde micro-capsules – Impact of process parameters on size distribution - Mixing speed - Mixing time Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 12

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Characterisation of microcapsules • Overview Nano indentation Morphology (optical microscopy, SEM) Particle size distribution Leaching of active ingredients … Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 13

Characterisation of microcapsules • Mechanical properties – Using nano-indentation technique Visco-elastic properties • Stiffness Elasticity Hardness – Flat punch tip (100 µm width) Load displacement curve Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 14

Characterisation of microcapsules: automated • Mechanical properties – Melamine formaldehyde micro-capsules  effect of size on capsule stiffness 16 14 12 10 8 6 4 2 20-50 60-80 80-90 90-100 140-170 Diameter (µm) S (mN/µm) Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 15 11

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine formaldehyde micro-capsules – Encapsulation of cyclohexane – Multi-parameter space to be optimized Core/ shell ratio? Shell type? Surfactant type ? Mixing speed? pH? Temperature? Core/surfac - tant ratio? Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 16

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study Goal The aim of this work is to present a combinatorial approach to enhance the investigation on a variety of synthesis and process parameters for the preparation of cyclohexane containing melamine-formaldehyde microcapsules DoE Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 17

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine – Recipe formaldehyde micro-capsules Reactor A • pH adjustment (9,5 ± 0,5) • Heating profile • Reaction Pre-condensate Reactor B • High shear mixing • pH adjustment (5,5 ± 0,15) Pre-emulsion Reactor B • pH adjustment during pre-condendate solution to pre-emulsion (5,15 ± 0,15) • Heating profile • Condensation reaction Condensation Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 18

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine formaldehyde microcapsules Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 19

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine formaldehyde micro-capsules Effect of surfactant and surfactant ratio on the morphology 30 µm 140 µm 290 µm 18 5 wt% Tween 20 shell/core = 1.5 5 wt% PSMA shell/core = 1.5 2,5 wt% PSMA shell/core = 1.5 PSMA: poly(styrene-maleic anhydride) Tween 20: Polyoxyethylene (20) sorbitan monolaurate Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 20

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine formaldehyde micro-capsules Effect of surfactant on the microcapsule formation 50 µm 100 µm PSMA/PVA (1 wt%) core/shell=1.5 SDS/PVA (1 wt%) core/shell=1.5 PSMA: poly(styrene-maleic anhydride) PVA: polyvinylalcohol SDS: Sodium dodecyl sulfate Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 21

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Case study • Melamine formaldehyde micro-capsules Effect of surfactant on the microcapsule formation 30 µm 50 µm SDS (1 wt%) core/shell=1 PSMA/SDS (1%) core/shell=0.5 Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 22

Case study Melamine formaldehyde micro-capsules • Melamine formaldehyde micro-capsules Effect of surfactant on the microcapsule formation PSMA/Tween (1 wt%) core/shell=1.0 10 µm 50 µm Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 23

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Conclusions • A unique platform for automated capsule synthesis and characterization, allowing – Composition screening – Process conditions screening • Speeding-up the complete material development chain Synthesis Formulation Application Devices Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 24

Int. Conference on high-throughput materials R&D, Ghent – 02-04 June Acknowledgements • Flamac – Pieter Castelein Geoffrey Coppens Tom Parasote Karen Verheyen Johan Paul • UAntwerpen • UGent – Dr. Dhanya Puthenmadom Prof. Nick Schryvers – Prof. Filip Du Prez Dr. Guadalupe Rivero Michel De Keersmacker (SEM) Int. Conference on high-throughput materials R&D, Ghent – 02-04 June 25