The nature of self-assembled octadecylphosphonic acid (ODPA) layers on copper substrates

• Hypothesis: The self-assembly of amphiphilic molecules onto solid substrates can result both in the formation of monolayers and multilayers. However, on oxidized and non-oxidized copper (Cu), only monolayer formation was reported for phosphonic acids possessing one phosphate head group. Here, the adsorption of octadecylphosphonic acid (ODPA) on Cu substrates through a self-assembly process was investigated with the initial hypothesis of monolayer formation. Experiments: The relative amount of ODPA adsorbed on a Cu substrate was determined by infrared reflection/absorption spectroscopy (IRRAS) and by atomic force microscopy (AFM) investigations before and after ODPA deposition. X-ray photoelectron spectroscopy (XPS) with sputtering was used to characterize the nature of the layers. Findings: The results show that the thickness of the ODPA layer increased with deposition time, and after 1 h a multilayer film with a thickness of some tens of nm was formed. The film was robust and required long-time sonication for removal. The origin of the film robustness was attributed to the release of Cu ions, resulting in the formation of Cu-ODPA complexes with Cu ions in the form of Cu(I). Preadsorbing a monolayer of octadecylthiol (ODT) onto the Cu resulted in no ODPA adsorption, since the release of Cu(I) ions was abolished.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

Atomic force microscopy

Copper leaching

Infrared reflection/absorption spectroscopy

Octadecylphosphonic acid

Self-assembled monolayers

X-ray photoelectron spectroscopy

Copper metallography

Deposition

Heavy ions

Monolayers

Multilayer films

Multilayers

Substrates

X ray photoelectron spectroscopy

Amphiphilic molecules

Copper substrates

Infrared reflections

Initial hypothesis

Monolayer formation

Octadecylphosphonic acids

Phosphonic acids

Self assembly process

Copper compounds

copper ion

octadecylthiol

phosphonic acid derivative

self assembled monolayer

thiol derivative

unclassified drug

absorption spectroscopy

acid deposition

adsorption

analytic method

Article

chemical analysis

chemical structure

cheminformatics

complex formation

controlled study

film thickness

infrared spectroscopy

priority journal

reflectometry

ultrasound

X ray photoemission spectroscopy

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)