TY - JOUR
T1 - Surface composition of mixed self-assembled monolayers on Au by infrared attenuated total reflection spectroscopy
AU - Tricase, Angelo
AU - Blasi, Davide
AU - Favia, Alessandro
AU - Stefanachi, Angela
AU - Leonetti, Francesco
AU - Colafemmina, Giuseppe
AU - Torsi, Luisa
AU - Scamarcio, Gaetano
N1 - Funding Information:
This work was partly supported by the European Union's Horizon 2020 research and innovation programme SiMBiT [grant agreement No. 824946]; the Italian ministry MIUR [grants e-DESIGN (ARS01_01158); PMGB (ARS01_01195); IDF SHARID (ARS01_01270)]; the Academy of Finland [projects #316881, #316883, #332106]; ?bo Akademi University and CSGI (Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grandi Interfasi)
Funding Information:
This work was partly supported by the European Union’s Horizon 2020 research and innovation programme SiMBiT [grant agreement No. 824946]; the Italian ministry MIUR [grants e-DESIGN (ARS01_01158); PMGB (ARS01_01195); IDF SHARID (ARS01_01270)]; the Academy of Finland [projects #316881, #316883, #332106]; Åbo Akademi University and CSGI (Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grandi Interfasi)
Publisher Copyright:
© 2021 The Authors
PY - 2021/9/1
Y1 - 2021/9/1
N2 - Self-assembled monolayers (SAMs) of N-(2-hydroxyethyl)-3-mercaptopropanamide (NMPA) were synthesized directly on the surface of electron-beam evaporated Au films, starting from 3-mercaptopropionic acid (3MPA) via ethyl-3-(3-dimethylamino-propyl)carbodiimide/N-hydroxysulfosuccinimide sodium salt (EDC/NHSS) coupling with ethanolamine hydrochloride. The influence on the reaction yield of the acidity of EDC/NHSS solutions (pH = 5.6 or 4.8) was assessed by exploiting the high surface sensitivity of infrared attenuated total reflection spectroscopy. The light-matter interaction was modeled in the framework of a matrix formalism considering the complete multi-layer sample structure. A comparison between the relative intensity of the main absorption bands, associated with amide I and carbonyl stretching of carboxylic acid or amide II vibrations, with a calibration curve obtained from the measurement of mixed 3MPA/NMPA SAMs, show that the more acid solution is 16% more efficient. This is mostly due to the higher protonation of the 3MPA.
AB - Self-assembled monolayers (SAMs) of N-(2-hydroxyethyl)-3-mercaptopropanamide (NMPA) were synthesized directly on the surface of electron-beam evaporated Au films, starting from 3-mercaptopropionic acid (3MPA) via ethyl-3-(3-dimethylamino-propyl)carbodiimide/N-hydroxysulfosuccinimide sodium salt (EDC/NHSS) coupling with ethanolamine hydrochloride. The influence on the reaction yield of the acidity of EDC/NHSS solutions (pH = 5.6 or 4.8) was assessed by exploiting the high surface sensitivity of infrared attenuated total reflection spectroscopy. The light-matter interaction was modeled in the framework of a matrix formalism considering the complete multi-layer sample structure. A comparison between the relative intensity of the main absorption bands, associated with amide I and carbonyl stretching of carboxylic acid or amide II vibrations, with a calibration curve obtained from the measurement of mixed 3MPA/NMPA SAMs, show that the more acid solution is 16% more efficient. This is mostly due to the higher protonation of the 3MPA.
KW - Attenuated total reflection spectroscopy
KW - Biofunctionalized interfaces
KW - Self-assembled monolayers
UR - http://www.scopus.com/inward/record.url?scp=85110492846&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2021.149883
DO - 10.1016/j.apsusc.2021.149883
M3 - Article
AN - SCOPUS:85110492846
SN - 0169-4332
VL - 559
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 149883
ER -