Senior Thin-film Materials Engineer (hydrophobic)

We are looking for a Senior Thin-film Materials Engineer to develop the hydrophobic liquid-facing surface of Rivercell's microfluidic chip. You will own the hydrophobic coating and the interfaces that determine wetting, adhesion, electrical stability, and compatibility with biological fluids. You will combine surface chemistry, coating development, and dynamic wetting characterization.

You will work hand-in-hand with our thin-film materials engineers, device integration lead, characterization engineer, and chip assembly team and an interdisciplinary team spanning genetic engineering, AI and software, bio-laboratory automation, optics, electronics, and biology. You will be an integral part of an ambitious and exciting French startup project from its inception.

Develop fluoropolymer and alternative hydrophobic coating processes for the microfluidic chip Optimize coating thickness, uniformity, roughness, surface energy, contact angle, contact-angle hysteresis and other relevant properties Engineer adhesion between hydrophobic coatings and underlying chip surfaces Characterize static and dynamic wetting behavior under water, oil, buffers, salts, cell-culture media, and representative biological reagents Study coating stability under repeated electrical actuation, immersion, cleaning, thermal cycling, storage, and handling

Investigate delamination, pinholes, swelling, contamination, adsorption, wetting degradation, and dielectric failure near the liquid interface Define surface-specific process windows, quality controls, handling procedures, and acceptance criteria

Evaluate alternative surface chemistries and scalable coating methods as the device moves toward manufacturing Opportunity to work on a cutting-edge project in the field of biotech Opportunity to join an ambitious team and impactful startup among the first employees Competitive salary and equity package Exciting opportunities for personal and professional growth within the team

a PhD in materials science, interface science, chemistry, chemical engineering, or a related field.

• You have 4+ years of relevant experience in polymer or fluoropolymer coatings, surface functionalization, adhesion, wetting, or liquid–solid interfaces.
• You combine strong technical judgment with a willingness to work hands-on in the laboratory and solve practical problems.
• You are autonomous, committed, enthusiastic, and comfortable working with a can-do, creative, and challenging mindset.
• You are rigorous in experiment design, documentation, data interpretation, and communication of uncertainty.
• You have excellent communication skills and are fluent in English; professional proficiency in French is helpful but not required.
• You have previous experience or knowledge in one or more of the following areas: Surface chemistry, silanization, plasma treatment, and thin coating processes Contact-angle measurement and dynamic wetting characterization Thin film dielectric breakdown Adhesion, interfacial failure, contamination control, and surface metrology Polymers or fluoropolymers used in microfluidic, electronic, optical, or biomedical devices Surface micropatterning and nanopatterning Experimental design and quantitative interpretation of surface-performance data Please let us know in your application if you specifically have experience with one or several of the following: Teflon AF, Cytop, PTFE, fluorosilanes, or related low-surface-energy materials Electrowetting, digital microfluidics, or liquid-facing dielectric coatings Surface micropatterning and nanopatterning AFM, XPS, ellipsometry, profilometry, surface-energy analysis, impedance spectroscopy or adhesion testing Biological-media compatibility and fouling mitigation

Throughout the recruiting process, you will meet 4 to 6 team members of Rivercell. Introductory call (up to 30mn, videocall) Technical interview (up to 90mn) Performance interview (up to 90mn, in person) Culture interview (up to 60mn, in person)