TY  - JOUR
A1  - Koc, Julian
A1  - Schardt, Lisa
A1  - Nolte, Kim
A1  - Beyer, Cindy
A1  - Eckhard, Till
A1  - Schwiderowski, Philipp
A1  - Clarke, Jessica L.
A1  - Finlay, John A.
A1  - Clare, Anthony S.
A1  - Muhler, Martin
A1  - Laschewsky, André
A1  - Rosenhahn, Axel
T1  - Effect of dipole orientation in mixed, charge-equilibrated self-assembled monolayers on protein adsorption and marine biofouling
JF  - ACS applied materials & interfaces
N2  - While zwitterionic interfaces are known for their excellent low-fouling properties, the underlying molecular principles are still under debate. In particular, the role of the zwitterion orientation at the interface has been discussed recently. For elucidation of the effect of this parameter, self-assembled monolayers (SAMs) on gold were prepared from stoichiometric mixtures of oppositely charged alkyl thiols bearing either a quaternary ammonium or a carboxylate moiety. The alkyl chain length of the cationic component (11-mercaptoundecyl)-N,N,N-trimethylammonium, which controls the distance of the positively charged end group from the substrate's surface, was kept constant. In contrast, the anionic component and, correspondingly, the distance of the negatively charged carboxylate groups from the surface was varied by changing the alkyl chain length in the thiol molecules from 7 (8-mercaptooctanoic acid) to 11 (12-mercaptododecanoic acid) to 15 (16-mercaptohexadecanoic acid). In this way, the charge neutrality of the coating was maintained, but the charged groups exposed at the interface to water were varied, and thus, the orientation of the dipoles in the SAMs was altered. In model biofouling studies, protein adsorption, diatom accumulation, and the settlement of zoospores were all affected by the altered charge distribution. This demonstrates the importance of the dipole orientation in mixed-charged SAMs for their inertness to nonspecific protein adsorption and the accumulation of marine organisms. Overall, biofouling was lowest when both the anionic and the cationic groups were placed at the same distance from the substrate's surface.
KW  - SAM
KW  - antifouling coatings
KW  - zwitterionic
KW  - XPS
KW  - Navicula perminuta
KW  - Ulva linza
KW  - SPR
Y1  - 2020
U6  - https://doi.org/10.1021/acsami.0c11580
SN  - 1944-8244
SN  - 1944-8252
VL  - 12
IS  - 45
SP  - 50953
EP  - 50961
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Madaan, Nitesh
A1  - Romriell, Naomi
A1  - Tuscano, Joshua
A1  - Schlaad, Helmut
A1  - Linford, Matthew R.
T1  - Introduction of thiol moieties, including their thiol-ene reactions and air oxidation, onto polyelectrolyte multilayer substrates
JF  - Journal of colloid and interface science
KW  - Thiol-ene
KW  - Layer-by-layer
KW  - XPS
KW  - ToF-SIMS
KW  - Hydrophobic
KW  - AFM
KW  - Ellipsometry
Y1  - 2015
U6  - https://doi.org/10.1016/j.jcis.2015.08.017
SN  - 0021-9797
SN  - 1095-7103
VL  - 459
SP  - 199
EP  - 205
PB  - Elsevier
CY  - San Diego
ER  -