With the increasing involvement and consciousness of citizens in themes like environment and health, there is a
demand for cheap, wireless, portable and easy to interpret sensors. The recently organized ‘Curieuzeneuzen’
measurement campaign in Flanders/Belgium, assessing the air quality by performing 20,000 lab-based analyses
of samplers collected in front of home windows, attests this clearly.
The induction of a color change as a response to a changing condition is an approach that can be easily
understood and implemented by a non-expert public. In the present project, an optical approach is pursued to
induce a color change based on the interaction of molecules or electromagnetic radiation with receptors on
optically active structured microparticles. These microparticles allow for a straightforward deposition on a wide
range of matrices like cloths, bandages, or coatings.
To manufacture optically active microparticles, innovative microfluidic approaches will be developed to meet the
stringent structural requirements for the desired optical response towards, e.g. UV, acidity or SO2 concentration.
Compositional and structural tolerance guidelines will be first produced by optical modeling. In parallel,
microfluidic channel designs to rapidly direct the particles towards reactive streams and build the optically active
particle layer-by-layer (LbL) will be first modeled and subsequently developed using advanced microfabrication
technologies. The chemistry used for the reversible responsive behaviour, as well as the nanoparticles used for
their compatible refractive index, require a close interplay with the optical modeling and experimental optical
This multidisciplinary project between 3 VUB and 2 UCL groups has the potential to lead to cheap, miniaturized,
non-electronic, battery-free and mass manufacturable sensors that can be integrated in existing textile and
coating practices for many consumer products. They will improve the quality of life by providing qualitative
information on e.g. desirable and undesirable environmental or atmospheric conditions. The microfluidic
manufacturing methodology is furthermore conceived in such a fashion that the receptors (and thus the chemical
or condition triggering the color change) can be easily changed without altering the manufacturing process,
making this approach a platform technology for the integration of new receptors types towards given molecules.
By changing the receptor concentration also quantitative information can be obtained. Also in the absence of
receptors, the structurally colored particles are interesting for their function as dyes, because they will not be
prone to photobleaching, a phenomenon classical dyes suffer from. A Brussels based spin-off that produces the
photosensitive material as original equipment manufacturer is mainly targeted. The partners of the project have
already shown a strong interest for this technology because it might be a game-changer in their respective
Effective start/end date1/03/1921/02/22

    Research areas

  • Microfluidics, 1D photonic bragg stack, responsive polymer, layer-by-layer deposition, sensors

    Flemish discipline codes

  • Environmental technologies

ID: 44101414