Sample of any longer material (5)
I believe the answer is:
nylon
'material' is the definition.
(nylon is a kind of material)
'sample of any longer' is the wordplay.
'sample of' indicates a hidden word (an extract or sample of the clue).
'NYLON' is hidden within 'any longer'.
(Other definitions for nylon that I've seen before include "Plastic used for stockings" , "Fabric (originally from New York and London)" , "Hosiery material" , "A thermoplastic" , "Stocking; polymer" .)