M.T. (Matthijs) Alting MSc

M.T. (Matthijs) Alting MSc

Promovendus
Physical and Colloid Chemistry
030 253 3406
m.t.alting@uu.nl

In 2005 a new class of soft-materials consisting of two interpenetrating, continuous networks of immiscible liquids was introduced [1]. These rigid structures are known as bicontinuous interfacially jammed emulsion gels (bijels) which are stabilized by a jammed layer of colloidal nanoparticles (NPs). Their high surface-area porous channel network, containing both an oil- and water phase and the presence of NPs lead to potential applications in various areas like catalysis, separation mediums and sensors [1]–[4].

In this project, we will investigate the catalytic application of bijels as new type of industrial reactor. Nowadays, the syntheses of chemicals and pharmaceuticals consume large amounts of energy, leave toxic solvent waste behind and utilize over 15% of the global energy consumption to purify the products [5], [6]. Bijels can reduce this expenditure since the reaction and separation occur simultaneously within one single step. Due to the different liquid polarities, both the reactants and products can partition into one of the phases (figure 1). Furthermore, bijels can facilitate close contact between immiscible reagents. This renders the use of organic solvent superfluous, making catalytic bijels economically feasible too [7], [8].

The main objectives of this project are to prepare, characterize and test catalytically active bijels. Different NPs which can both stabilize the immiscible liquids and are catalytically active will be tested. Preparation will be executed by the valuable method of solvent transfer induced phase separation (STrIPS) using microfluidic devices to enable continuous fabrication of bijel fibers [9], [10]. Characterization will be performed using confocal, optical and electron microscopy. Examples of industrial biphasic reactions e.g. hydrolysis and esterification, will be tested in homogeneous and/or heterogeneous conditions. A continuous flow reactor out of these bijels will be constructed using photolithography. The flow of fluids throughout the pore network will be realized using an electroosmotic or pressure-driven flow.

Figure 1: Schematic representation of a bicontinuous flow through a bijel network containing a catalytically active layer of NPs in an esterification of oleic acid to biodiesel. The reaction between oleic acid and (an excess of) methanol and the separation of the products methyl oleate and water occur in a single step at the liquid-liquid interface. Methyl oleate ends up in the apolar oil phase, where water and the excess of methanol remain in the polar phase. Figure and reaction inspired by ref. [4], [11].

 

References

  1. K. Stratford et al., Science 309, 2198-2201 (2005)
  2. M. F. Haase et al., ACS Nano 10, 6338-6344 (2016)
  3. E. M. Herzig et al., Nat. Mater 6, 966-971 (2007)
  4. M. E. Cates and P. S. Clegg, Soft Matter 4, 2132-2138 (2008)
  5. D. S. Sholl and R. P. Lively, Nature 532, 435-438 (2016)
  6. S. Crossley et al., Science 327, 68-72 (2010)
  7. G. Di Vitantonio et al., Appl. Phys. Rev. 8, 021323-1-14 (2021)
  8. S. Cha et al., Sci. Rep. 9, 6363-1-6 (2019)
  9. M. F. Haase et al., Chapter 6 from ‘Soft Matter Series No. 10’, (2020)
  10. M. F. Haase et al., Adv. Mater. 27, 7065-7071 (2015)
  11. S. Mohebbi et al., Fuel 266, 117063-1-8 (2020)