Odd-even effect in the hydrophobicity of n-alkanethiolate self-assembled monolayers depends upon the roughness of the substrate and the orientation of the terminal moiety

The origin of the odd-even effect in properties of self-assembled monolayers (SAMs) and/or technologies derived from them is poorly understood. We report that hydrophobicity and, hence, surface wetting of SAMs are dominated by the nature of the substrate (surface roughness and identity) and SAM tilt...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 30(2014), 40 vom: 14. Okt., Seite 11985-92
1. Verfasser: Newcomb, Lucas B (VerfasserIn)
Weitere Verfasser: Tevis, Ian D, Atkinson, Manza B J, Gathiaka, Symon M, Luna, Rafael E, Thuo, Martin
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2014
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Alkanes Sulfhydryl Compounds Water 059QF0KO0R Silver 3M4G523W1G Gold 7440-57-5
LEADER 01000naa a22002652 4500
001 NLM242014739
003 DE-627
005 20231224125501.0
007 cr uuu---uuuuu
008 231224s2014 xx |||||o 00| ||eng c
024 7 |a 10.1021/la5032569  |2 doi 
028 5 2 |a pubmed24n0806.xml 
035 |a (DE-627)NLM242014739 
035 |a (NLM)25233063 
040 |a DE-627  |b ger  |c DE-627  |e rakwb 
041 |a eng 
100 1 |a Newcomb, Lucas B  |e verfasserin  |4 aut 
245 1 0 |a Odd-even effect in the hydrophobicity of n-alkanethiolate self-assembled monolayers depends upon the roughness of the substrate and the orientation of the terminal moiety 
264 1 |c 2014 
336 |a Text  |b txt  |2 rdacontent 
337 |a ƒaComputermedien  |b c  |2 rdamedia 
338 |a ƒa Online-Ressource  |b cr  |2 rdacarrier 
500 |a Date Completed 15.06.2015 
500 |a Date Revised 14.10.2014 
500 |a published: Print-Electronic 
500 |a Citation Status MEDLINE 
520 |a The origin of the odd-even effect in properties of self-assembled monolayers (SAMs) and/or technologies derived from them is poorly understood. We report that hydrophobicity and, hence, surface wetting of SAMs are dominated by the nature of the substrate (surface roughness and identity) and SAM tilt angle, which influences surface dipoles/orientation of the terminal moiety. We measured static contact angles (θs) made by water droplets on n-alkanethiolate SAMs with an odd (SAM(O)) or even (SAM(E)) number of carbons (average θs range of 105.8-112.1°). When SAMs were fabricated on smooth "template-stripped" metal (M(TS)) surfaces [root-mean-square (rms) roughness = 0.36 ± 0.01 nm for Au(TS) and 0.60 ± 0.04 nm for Ag(TS)], the odd-even effect, characterized by a zigzag oscillation in values of θs, was observed. We, however, did not observe the same effect with rougher "as-deposited" (M(AD)) surfaces (rms roughness = 2.27 ± 0.16 nm for Au(AD) and 5.13 ± 0.22 nm for Ag(AD)). The odd-even effect in hydrophobicity inverts when the substrate changes from Au(TS) (higher θs for SAM(E) than SAM(O), with average Δθs |n - (n + 1)| ≈ 3°) to Ag(TS) (higher θs for SAM(O) than SAM(E), with average Δθs |n - (n + 1)| ≈ 2°). A comparison of hydrophobicity across Ag(TS) and Au(TS) showed a statistically significant difference (Student's t test) between SAM(E) (Δθs |Ag evens - Au evens| ≈ 5°; p < 0.01) but failed to show statistically significant differences on SAM(O) (Δθs |Ag odds - Au odds| ≈ 1°; p > 0.1). From these results, we deduce that the roughness of the metal substrate (from comparison of M(AD) versus M(TS)) and orientation of the terminal -CH2CH3 (by comparing SAM(E) and SAM(O) on Au(TS) versus Ag(TS)) play major roles in the hydrophobicity and, by extension, general wetting properties of n-alkanethiolate SAMs 
650 4 |a Journal Article 
650 4 |a Research Support, Non-U.S. Gov't 
650 4 |a Research Support, U.S. Gov't, Non-P.H.S. 
650 7 |a Alkanes  |2 NLM 
650 7 |a Sulfhydryl Compounds  |2 NLM 
650 7 |a Water  |2 NLM 
650 7 |a 059QF0KO0R  |2 NLM 
650 7 |a Silver  |2 NLM 
650 7 |a 3M4G523W1G  |2 NLM 
650 7 |a Gold  |2 NLM 
650 7 |a 7440-57-5  |2 NLM 
700 1 |a Tevis, Ian D  |e verfasserin  |4 aut 
700 1 |a Atkinson, Manza B J  |e verfasserin  |4 aut 
700 1 |a Gathiaka, Symon M  |e verfasserin  |4 aut 
700 1 |a Luna, Rafael E  |e verfasserin  |4 aut 
700 1 |a Thuo, Martin  |e verfasserin  |4 aut 
773 0 8 |i Enthalten in  |t Langmuir : the ACS journal of surfaces and colloids  |d 1992  |g 30(2014), 40 vom: 14. Okt., Seite 11985-92  |w (DE-627)NLM098181009  |x 1520-5827  |7 nnns 
773 1 8 |g volume:30  |g year:2014  |g number:40  |g day:14  |g month:10  |g pages:11985-92 
856 4 0 |u http://dx.doi.org/10.1021/la5032569  |3 Volltext 
912 |a GBV_USEFLAG_A 
912 |a SYSFLAG_A 
912 |a GBV_NLM 
912 |a GBV_ILN_22 
912 |a GBV_ILN_350 
912 |a GBV_ILN_721 
951 |a AR 
952 |d 30  |j 2014  |e 40  |b 14  |c 10  |h 11985-92