Vapour-phase　per-　and　polyfluoroalkyl　substances　(PFASs),　such　as　Fluorotelomer　alcohols　(FTOHs),　significantly　contribute　to　their　global　dissemination　and　bioaccumulation.　Adsorption　and　diffusion　are　the　fundamental　processes　that　govern　the　environmental　fate　of　PFASs　in　soil.　This　study　investigates　the　adsorption　and　diffusion　of　vapour-phase　FTOHs　in　unsaturated　nanopores　of　montmorillonite　and　kaolinite　using　molecular　dynamics　simulations.　Results　show　that　FTOH　adsorption　is　higher　on　montmorillonite　than　that　on　kaolinite.　Adsorption　capacity　in　montmorillonite　nanopores　increases　with　decreasing　moisture　content　and　decreasing　FTOHs　chain　length.　At　5　%　moisture,　the　peak　density　for　4:2　FTOH　on　montmorillonite　is　2.6　times　greater　than　at　10　%　moisture.　FTOH　adsorption　on　kaolinite　shows　minimal　dependence　on　moisture　content,　with　the　peak　density　of　FTOH　remaining　relatively　constant　at　different　moisture　levels.　Moreover,　the　distance　of　FTOHs　adsorbed　at　both　montmorillonite　and　kaolinite　surface　increases　with　increasing　moisture　content.　FTOHs　in　unsaturated　nanopores　adsorbed　mainly　via　interactions　between　the　oxygenated　head　and　the　mineral　surface,　with　FTOHs　adsorbing　at　an　angle　on　kaolinite　and　parallel　to　the　montmorillonite　surface　at　5　%　moisture　content.　At　15　%　moisture　content,　FTOHs　adsorption　on　montmorillonite　adopts　an　angle　of　approximately　32.3°.　Configurational　entropy　of　FTOHs　in　both　minerals　decreases　with　increasing　moisture　content　due　to　FTOH　molecular　aggregation.　The　interaction　between　FTOHs　and　kaolinite　is　weaker,　leading　to　greater　mobility　in　nanopores　of　kaolinite,　particularly　for　long-chain　FTOHs　(10:2　and　8:2).　These　findings　suggest　that　while　FTOHs,　as　precursors　to　PFASs,　can　be　immobilized　in　soils,　and　may　still　migrate　under　fluctuating　moisture　conditions.　©　2025　Elsevier　B.V.