Lead Scientist, Chemistry (Founding Team)

We build and finance impact-driven companies
with scalable and tech-based solutions to fight climate change

Place: Paris, France. Level: Senior, Contract: Permanent, Mode: Hybrid

Snapshot We're looking for a Lead Scientist in Chemistry to drive the chemistry direction of Thermia, bringing PFAS-free chemistry expertise into our AI and engineering teams, opening novel chemical directions, and steering the molecular portfolio from hypothesis to qualified product.

About Us Thermia is building multi-scale foundation models to discover the next generation of PFAS-free thermal fluids and systems. Our team is a tight-knit group of ML scientists, computational chemists, and thermal engineers working at the intersection of generative chemistry, scientific ML, and industrial thermal design. We are an early-stage company based in Paris.

The Role As Lead Scientist, you will be the core chemistry expert of the discovery loop. You will collaborate closely with the AI and technical teams, bringing deep insight on PFAS-free chemistry, novel and unexplored chemical families, blends, and structure-property relationships into the design of models, search criteria, and discovery campaigns. You will evaluate the candidates the system produces, build the scientific and industrial case for each, and steer the molecular portfolio all the way through synthesis and characterization with external partners.

Your work may involve:

• Collaborating with the AI and technical teams as the chemistry expert in the loop, feeding structured insights on PFAS-free chemistry, novel and unexplored families, blends, and structure-property relationships into model objectives, scoring functions, and exploration strategies

• Opening new chemical directions: identifying underexplored families, formulation strategies, and design hypotheses worth investing model and lab effort in

• Evaluating AI-generated candidates using state-of-the-art computational chemistry tools (DFT, MD, COSMO-RS, force fields, semi-empirical methods) and chemical intuition

• Proposing concrete improvements to candidates and refining the chemistry priors that guide the next round of generation

• Building the scientific and industrial case for each candidate including thermodynamic and thermophysical profile, expected performance, stability, safety, synthesizability and synthetic route, by-products and impurities, environmental and regulatory profile, ingredient sourcing and pricing, formulation viability, industrial constraints (scale-up, manufacturing, qualification), and IP landscape

• Owning the molecular portfolio: prioritizing candidates, tracking their progress, and making the call on what advances and what doesn't

• Guiding the bibliographic effort making sure the team is grounded in the right literature, prior art, and industrial context

• Engaging with external chemical companies, CROs, and academic partners, building relationships, scoping collaborations, and negotiating engagements

• Overseeing external synthesis and characterization efforts to ensure candidates are produced and qualified on time and to spec

• Communicating results clearly through technical reports, scientific reviews, and partner-facing material

About You

• 5+ years in chemistry, molecular design, or materials discovery in industry or applied research

• Deep expertise in PFAS-free chemistry, fluorinated alternatives, or related chemical families relevant to thermal fluids

• Working command of state-of-the-art computational chemistry tools (DFT, MD, COSMO-RS, or equivalent)

• Strong chemical intuition: you can look at a structure and know what to ask, what to compute, and what to worry about

• Track record of taking molecules from concept toward real-world application

• Strong communication and ability to translate between chemistry, AI, and business audiences

• High agency: you push projects forward, prioritize effectively, and take initiative

In addition, the following would be an advantage:

• Experience with thermal fluids, dielectric fluids, refrigerants, or related industrial fluid systems

• Experience with formulation and blends, not just single molecules

• Direct experience with PFAS replacement programs

• Experience managing external synthesis or CRO relationships

• Experience working closely with ML teams on molecular discovery

• A track record of publishing or speaking in chemistry venues