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Controlled sub‐10‐nanometer poly( N ‐isopropyl‐acrylamide) layers grafted from silicon by atom transfer radical polymerization
Author(s) -
Schulz Andreas S.,
Gojzewski Hubert,
Huskens Jurriaan,
Vos Willem L.,
Julius Vancso G.
Publication year - 2018
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.4187
Subject(s) - materials science , atom transfer radical polymerization , poly(n isopropylacrylamide) , polymer , polymerization , ellipsometry , polymer chemistry , silicon , nanometre , radical polymerization , chemical engineering , chain transfer , nanotechnology , composite material , thin film , copolymer , optoelectronics , engineering
Surface‐initiated atom transfer radical polymerization (SI‐ATRP) was used to graft poly( N ‐isopropylacrylamide) (PNIPAM) brush layers with a controllable thickness in the 10‐nm range from silicon substrates. The rate of polymerization of N ‐isopropylacrylamide was tuned by the [Cu(II)] 0 /[Cu(I)] 0 ratio between the deactivating and activating species. The polymer layer thickness was characterized by atomic force microscopy (AFM) and ellipsometry. PNIPAM layers with a dry thickness between 5.5 and 16 nm were obtained. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) confirmed that the chemical structure is PNIPAM brushes. Analysis of the AFM data showed that our procedure leads to polymer grafts in the “mushroom‐to‐brush” transition regime.