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Functionalization of self‐assembled monolayers on gold by UV‐induced graft polymerization
Author(s) -
Zhang Junfeng,
Cui Cheng Qiang,
Lim Thiam Beng,
Kang EnTang
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20000901)201:14<1653::aid-macp1653>3.0.co;2-f
Subject(s) - contact angle , x ray photoelectron spectroscopy , polymerization , monolayer , monomer , chemistry , polymer chemistry , surface modification , self assembled monolayer , copolymer , acrylic acid , polymer , adsorption , chemical engineering , organic chemistry , biochemistry , engineering
Further modification of self‐assembled monolayers (SAMs) on gold via argon plasma‐treatment and then UV‐induced graft polymerization with functional monomers has been carried out. Two alkanethiols, viz ., 3‐mercaptopropionic acid (MPA) and 3‐mercaptopropionic acid 2‐ethylhexyl ester (MPAEE), were employed for the deposition of SAMs from ethanol solutions onto gold surfaces. The monomers used for graft polymerization were water‐soluble acrylic acid (AAc) and hydrophobic allylpentafluorobenzene (APFB). Angle‐resolved X‐ray photoelectron spectroscopy (XPS) and contact angle measurements were used to investigate the surface chemical composition, surface coverage, film thickness, and wettablity. XPS results suggest that mild and brief plasma treatments can be employed to generate sufficient amounts of peroxides and hydroperoxides on the SAMs for the subsequent UV‐induced graft polymerization while maintaining the SAMs intact. For all the cases investigated, XPS results reveal that the graft polymer forms a thin layer of 6–7 nm in thickness on the SAM surfaces. Contact angle measurements indicate that the SAM‐modified Au surfaces could be selectively made hydrophilic or hydrophobic through the graft copolymerization with an appropriate monomer. It was also demonstrated that the AAc graft polymerized SAMs selectively adsorbed Fe 3+ ions via coordination complexation.