Multifunctional　flexible　devices　for　human　motion　detection　and　thermal　management　raised　great　at-tention　as　the　problem　of　the　aging　population　is　becoming　more　and　more　serious.　However,　it　is　still　a　challenge　to　endow　the　devices　with　excellent　stability　and　wide　application　scope.　Here　we　prepared　a　hydrophobic　and　conductive　fabric-based　strain　sensor　for　smart　fabric　via　successively　coating　with　poly　-dopamine　(PDA),　polyaniline　(PANI),　polypyrrole　(PPy),　and　polydimethylsiloxane　(PDMS)　through　in-situ　polymerization　and　dip-coating,　which　could　be　used　for　strain　sensor　and　wearable　heater　both　in　air　and　underwater.　The　obtained　sample　exhibited　a　fast　electrical　response　in　500　ms　and　could　withstand　10,0　0　0　times　stretching-releasing　cycles,　additionally,　the　sample　exhibited　satisfactory　electro-thermal　and　photo-thermal　performances.　As　a　whole,　the　multifunctional　fabric-based　devices　with　excellent　performances　show　great　potential　to　be　applied　in　medical　monitoring　and　personal　care,　especially　for　aged　and　disabled　persons.(c)　2022　Published　by　Elsevier　Ltd　on　behalf　of　The　editorial　office　of　Journal　of　Materials　Science　&　Technology.