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PhD project Jetting: rheologic investigations to achieve reproducible jetting with minimal

Job description

This project will be focused on characterization of liquid jets (diameter, length, volume, velocity, satellite droplets size distribution, etc.). The rheology of the jets made with a microfluidic device where cavitation takes place will be tuned to obtain predictable jets with velocities ∼100 m/s and diameters ≤50 μm. This will be achieved with additives and geometrical control of contact line and meniscus to focus energy. These jets should be able to penetrate the human skin.

The needle-free delivery of liquid jets into soft and heterogeneous substrates, e.g. human tissue, has been hindered by the need to reach specific penetration depths with energy efficient means, by the break-up of jets that impedes control over the dose delivery, and by liquid splash-back after impacting the substrate that causes cross-contamination between injections. BuBble Gun aims at overcoming these challenges.

BuBble gun will advance scientific knowledge at the intersection of microfluidics, physics, and bioengineering, to enable unprecedented physical understanding and control over cavitation, jetting, and injection phenomena. We will develop a portable energy-efficient injection platform by using ultra-high-speed imaging, and quantifying injections with experimental resolutions below the microsecond and micrometer scales. The rheological properties of the jets will be tuned with biocompatible additives to ensure cohesion, before injecting them into in-vitro targets and ex-vivo skin. Numerical models will assist in untangling the influence of microfluidic configuration and material properties on the injection outcome.

Your profile

  • You have a background in applied physics, mechanical or biomechanical engineering, or in a closely related discipline.
  • You have strong communication skills, including fluency in written and spoken English.
  • You are able to work independently, and have excellent theoretical and experimental skills.
  • Experience in modelling or in the laboratory in any level is appreciated. However, experience in microscopy, microfluidics, rheology, spectrometry, photonics and/or detection techniques will be considered as an advantage.
  • Team-working skills are expected from the candidate due to the multidisciplinary and collaborative approach of the project.

Our offer

We offer an excellent and stimulating scientific environment with an attractive campus and lots of facilities for sports and leisure. The university provides a dynamic ecosystem with enthusiastic colleagues in which internationalization is an important part of the strategic agenda.
You will have a fulltime employment contract for four years and can participate in all employee benefits the UT offers.
The gross monthly salary starts with € 2.395,- in the first year and increases to € 3.061,- in the fourth year of your employment;
You will receive a holiday allowance of 8% of the gross annual salary and a year-end bonus of 8.3%;
The research will result in a PhD thesis at the end of the employment period.

Information and application

If interested, please prepare *one* pdf document having the following parts:


  • A motivation letter describing why you apply for this position, with a description of your research interests (no more than 1 A4)
  • Email addresses of at least two references who are willing to send a letter of recommendation on your behalf
  • A detailed CV
  • Academic transcripts from your Bachelor’s and Master’s degrees.

An interview with a scientific presentation will be part of the interview process


Contact: Associate professor Dr. David Fernandez Rivas

Principal Investigator, Mesoscale Chemical Systems Group,

Faculty of Science and Technology TNW, University of Twente.



Applications are welcome until the position is filled.

This position is expected to start during the first trimester of 2021.

About the department

The research of the Mesoscale Chemical Systems (MCS) chair, headed by Han Gardeniers, originates from the group's unique expertise in micro and nanofabrication, backed by the outstanding experimental facilities of MESA+ NanoLab.

Focal points in the research are:

The development of 3D nanostructures for solar to electricity to chemical conversion
Microreactors as a means of chemical process intensification (sonochemistry, high pressure, electricity-driven)
Miniaturized analytical tools and MEMS-based sensors for a variety of application fields (forensics, health, environment, chemical process control)
Microfluidic systems for life science applications (e.g. drug delivery)

About the organization

University of Twente (UT)

University of Twente (UT) has entered the new decade with an ambitious, new vision, mission and strategy. As ‘the ultimate people-first university of technology' we are rapidly expanding on our High Tech Human Touch philosophy and the unique role it affords us in society. Everything we do is aimed at maximum impact on people, society and connections through the sustainable utilisation of science and technology. We want to contribute to the development of a fair, digital and sustainable society through our open, inclusive and entrepreneurial attitude. This attitude permeates everything we do and is present in every one of UT's departments and faculties. Building on our rich legacy in merging technical and social sciences, we focus on five distinguishing research domains: Improving healthcare by personalised technologies; Creating intelligent manufacturing systems; Shaping our world with smart materials; Engineering our digital society; and Engineering for a resilient world.

As an employer, University of Twente offers jobs that matter. We equip you as a staff member to shape new opportunities both for yourself and for our society. With us, you will be part of a leading tech university that is changing our world for the better. We offer an open, inclusive and entrepreneurial climate, in which we encourage you to make healthy choices, for example, with our flexible, customisable conditions.

PhD project Jetting: rheologic investigations to achieve reproducible jetting with minimal
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