Solvent-responsive wettability of self-assembled monolayers of dithiooctanoic acid derivatives bearing N,N-disubstituted amide groups.
We have designed and synthesized two dithiooctanoic acid derivatives bearing N,N-disubstituted amide groups and used them to fabricate self-assembled monolayers (SAMs) on gold surface. These films showed a reversible changes in wettability, one of which was indicated by surface contact angle switching between 40° and 59° upon alternating treatment with ethanol and cyclohexane. NMR experimental results of a model molecule suggest that the solvent-responsive wettability of the SAMs could be related with the changes in the relative populations of two stereoisomers of amide. The solvent responsivity of SAMs fabricated from other two amides was also studied, and the results confirmed that N,N-disubstitution was essential for an amide-containing SAM to have stimuli responsivity. Thus, introduction of a functional group exhibiting controlled isomerization of conformation could be an effective strategy for designing new stimuli-responsive materials.
State Key Laboratory of Supramolecular Structure and Materials, Jilin University , Changchun 130012, China.
Fangming
F
Liu
Juan
J
Pang
Chunyu
C
Wang
Liyan
L
Wang