Lead Scientist, Chemistry (Founding Team)

Thermia is the first AI-native solution vertically built for the industrial thermal chain, discovering breakthrough fluids and co-optimizing associated device, from Molecules to industrial systems.

We are a team of machine learning scientists, computational chemists, and thermal engineers united by a single ambition: to create a fundamentally new way of designing the fluids and systems that move heat through our modern economy.

Today's approach to thermal fluid and system design is fragmented, slow, and structurally incompatible with the urgency of the energy transition. Chemists develop fluids without knowledge of the systems they will run in. Engineers design thermal hardware without optimizing the working fluid. The result is decades of R&D, billions in cost and solutions that are sub-optimal by construction.

Thermia replaces this fragmented process with an integrated, physics-grounded discovery pipeline: AI accelerates what human expertise makes possible, and experiments validate what AI generates. Our platform generates entirely novel molecular candidates and co-optimizes the thermal systems associated with each discovery, building a proprietary portfolio of qualified molecules, fine-tuned models, and experimental data with every engagement.

Our work is powering the thermal infrastructure the energy transition cannot wait for.

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.

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