Evaporation dynamics of microdroplets on self-assembled monolayers of dialkyl disulfides

We present a study of the static wettability and evaporation dynamics of sessile microdroplets of water on self-assembled monolayers (SAMs) prepared with unsymmetric dialkyl disulfides CH(3)-(CH(2))(11+m)-S-S-(CH(2))(11)-OH (m = 0, +/- 2, +/- 4, +/- 6) on gold-covered mica. The advancing and recedin...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 25(2009), 23 vom: 01. Dez., Seite 13438-47
1. Verfasser: Li, Guangfen (VerfasserIn)
Weitere Verfasser: Flores, Susana Moreno, Vavilala, Chandrasekhar, Schmittel, Michael, Graf, Karlheinz
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2009
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Disulfides
LEADER 01000naa a22002652 4500
001 NLM192359495
003 DE-627
005 20231223192851.0
007 cr uuu---uuuuu
008 231223s2009 xx |||||o 00| ||eng c
024 7 |a 10.1021/la901422v  |2 doi 
028 5 2 |a pubmed24n0641.xml 
035 |a (DE-627)NLM192359495 
035 |a (NLM)19863053 
040 |a DE-627  |b ger  |c DE-627  |e rakwb 
041 |a eng 
100 1 |a Li, Guangfen  |e verfasserin  |4 aut 
245 1 0 |a Evaporation dynamics of microdroplets on self-assembled monolayers of dialkyl disulfides 
264 1 |c 2009 
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 01.02.2010 
500 |a Date Revised 25.11.2009 
500 |a published: Print 
500 |a Citation Status MEDLINE 
520 |a We present a study of the static wettability and evaporation dynamics of sessile microdroplets of water on self-assembled monolayers (SAMs) prepared with unsymmetric dialkyl disulfides CH(3)-(CH(2))(11+m)-S-S-(CH(2))(11)-OH (m = 0, +/- 2, +/- 4, +/- 6) on gold-covered mica. The advancing and receding contact angles decrease linearly with increasing hydrophilicity of the SAM. The latter was changed either via the molar ratio or via the chain length of the hydroxyl-terminated alkyl chains in the monolayer. In contrast to SAMs made of thiols, the contact angle hysteresis was 10 degrees for all disulfides, irrespective of their chain lengths. During evaporation of single droplets, a transition from pinning to constant contact angle mode was observed. The transition time between the modes increases with the surface hydrophilicity, leading to longer pinning. This way, the time for complete droplet evaporation decreases by approximately 30% owing to the fact that during pinning the overall droplet area stays large for a longer time. For single droplets the measured total evaporation times agree well with the calculated ones, showing the validity of the standard evaporation model for both evaporation modes. In contrast to the results for single droplets, many droplets with different initial volumes show a power-law dependence on the total evaporation time with an exponent different from 1.5 as expected from the standard model. For disulfides with m not equal 0, the exponent is in the range of 1.40-1.47 increasing with the surface hydrophilicity. For the SAMs with m = 0 the exponent increases up to 1.61 for the most hydrophilic surface. We explain this deviation from the standard evaporation model with the presence of a liquid precursor film around the droplet, which either enhances or decelerates evaporation. Our results suggest that SAMs of dialkyl disulfides offer the possibility to tune the wettability of gold surfaces in a more controlled way than thiols do 
650 4 |a Journal Article 
650 4 |a Research Support, Non-U.S. Gov't 
650 7 |a Disulfides  |2 NLM 
700 1 |a Flores, Susana Moreno  |e verfasserin  |4 aut 
700 1 |a Vavilala, Chandrasekhar  |e verfasserin  |4 aut 
700 1 |a Schmittel, Michael  |e verfasserin  |4 aut 
700 1 |a Graf, Karlheinz  |e verfasserin  |4 aut 
773 0 8 |i Enthalten in  |t Langmuir : the ACS journal of surfaces and colloids  |d 1992  |g 25(2009), 23 vom: 01. Dez., Seite 13438-47  |w (DE-627)NLM098181009  |x 1520-5827  |7 nnns 
773 1 8 |g volume:25  |g year:2009  |g number:23  |g day:01  |g month:12  |g pages:13438-47 
856 4 0 |u http://dx.doi.org/10.1021/la901422v  |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 25  |j 2009  |e 23  |b 01  |c 12  |h 13438-47