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Direct Evidence for the Polymeric Nature of Polydopamine
Author(s) -
Delparastan Peyman,
Malollari Katerina G.,
Lee Haeshin,
Messersmith Phillip B.
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201811763
Subject(s) - polymer , surface modification , force spectroscopy , adhesive , covalent bond , materials science , polymer science , nanotechnology , non covalent interactions , aggregate (composite) , characterization (materials science) , molecule , polymer chemistry , chemical engineering , chemistry , atomic force microscopy , hydrogen bond , composite material , organic chemistry , layer (electronics) , engineering
Inspired by the adhesive proteins of mussels, polydopamine (pDA) has emerged as one of the most widely employed materials for surface functionalization. Despite numerous attempts at characterization, little consensus has emerged regarding whether pDA is a covalent polymer or a noncovalent aggregate of low molecular weight species. Here, we employed single‐molecule force spectroscopy (SMFS) to characterize pDA films. Retraction of a pDA‐coated cantilever from an oxide surface shows the characteristic features of a polymer with contour lengths of up to 200 nm. pDA polymers are generally weakly bound to the surface through much of their contour length, with occasional “sticky” points. Our findings represent the first direct evidence for the polymeric nature of pDA and provide a foundation upon which to better understand and tailor its physicochemical properties.