Comparative XPS Study of Copper, Nickel, and Aluminum Coatings on Polymer Surfaces

Bébin, Philippe; Prud’homme, Robert E.

doi:10.1021/cm020599x

Cited by 50 publications

(52 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The appearance of TiC peaks in the X-ray photoelectron spectroscopy (XPS) spectra indicated covalent bonds between Ti atoms and C atoms in PMMA. XPS investigations by Bébin and Prud'homme of Ni nanofilms on PMMA showed that Ni reacted with the oxygen in the PMMA molecule [51]. This led to formation of nickel oxide, and a covalent bond at the metal-polymer interface.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Thermal Boundary Conductance of Metal–Polymer System

et al. 2020

View full text Add to dashboard Cite

In organic electronics, thermal management is a challenge, as most organic materials conduct heat poorly. As these devices become smaller, thermal transport is increasingly limited by organic–inorganic interfaces, for example that between a metal and a polymer. However, the mechanisms of heat transport at these interfaces are not well understood. In this work, we compare three types of metal–polymer interfaces. Polymethyl methacrylate (PMMA) films of different thicknesses (1–15 nm) were spin-coated on silicon substrates and covered with an 80 nm gold film either directly, or over an interface layer of 2 nm of an adhesion promoting metal—either titanium or nickel. We use the frequency-domain thermoreflectance (FDTR) technique to measure the effective thermal conductivity of the polymer film and then extract the metal–polymer thermal boundary conductance (TBC) with a thermal resistance circuit model. We found that the titanium layer increased the TBC by a factor of 2, from 59 × 106 W·m−2·K−1 to 115 × 106 W·m−2·K−1, while the nickel layer increased TBC to 139 × 106 W·m−2·K−1. These results shed light on possible strategies to improve heat transport in organic electronic systems.

show abstract

Section: Resultsmentioning

confidence: 99%

Enhancement of Thermal Boundary Conductance of Metal–Polymer System

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The top electrode is produced only at a later stage, when the upper surface of the film is capped with a second layer of metal, evaporated in the same conditions as the lower electrode. Aluminum is preferred to other metals because of the sharpness of the interfaces between this element and several polymers [49]. Evaporated on top of a polymer film, gold, on the contrary, tend to diffuse through the organic medium.…”

Section: Nanocapacitors (Capped Films)mentioning

confidence: 99%

Glassy dynamics of soft matter under 1D confinement: How irreversible adsorption affects molecular packing, mobility gradients and orientational polarization in thin films

2013

View full text Add to dashboard Cite

The structural dynamics of polymers and simple liquids confined at the nanometer scale has been intensively investigated in the last two decades in order to test the validity of theories on the glass transition predicting a characteristic length scale of a few nanometers. Although this goal has not yet been reached, the anomalous behavior displayed by some systems--e.g. thin films of polystyrene exhibit reductions of Tg exceeding 70 K and a tremendous increase in the elastic modulus--has attracted a broad community of researchers, and provided astonishing advancement of both theoretical and experimental soft matter physics. 1D confinement is achieved in thin films, which are commonly treated as systems at thermodynamic equilibrium where free surfaces and solid interfaces introduce monotonous mobility gradients, extending for several molecular sizes. Limiting the discussion to finite-size and interfacial effects implies that film thickness and surface interactions should be sufficient to univocally determine the deviation from bulk behavior. On the contrary, such an oversimplified picture, although intuitive, cannot explain phenomena like the enhancement of segmental mobility in proximity of an adsorbing interface, or the presence of long-lasting metastable states in the liquid state. Based on our recent work, we propose a new picture on the dynamics of soft matter confined in ultrathin films, focusing on non-equilibrium and on the impact of irreversibly chain adsorption on the structural relaxation. We describe the enhancement of dynamics in terms of the excess in interfacial free volume, originating from packing frustration in the adsorbed layer (Guiselin brush) at t(*) ≪ 1, where t(*) is the ratio between the annealing time and the time scale of adsorption. Prolonged annealing at times exceeding the reptation time (usually t(*) ≫ 1 induces densification, and thus reduces the deviation from bulk behavior. In this Colloquium, after reviewing the experimental approaches permitting to investigate the structural relaxation of films with one, two or no free surfaces by means of dielectric spectroscopy, we propose several methods to determine gradients of mobility in thin films, and then discuss on the unexploited potential of analyses based on the time, temperature and thickness dependence of the orientational polarization via the dielectric strength.

show abstract

“…We did not consider varying the evaporation rate of the upper metallic layer, because this parameter would not affect the polymer-metal interface. Al, in fact, forms via weak dispersive forces very sharp interfaces when evaporated onto polymers and it does not diffuse into the polymer during the measurement time [27]. The fabricated nanocapacitors were placed in a dielectric cell and stabilized in a thermostat in a dry He atmosphere before investigation via an impedance analyzer (ModuLab XM MTS, Solartron Analytical), in a broad temperature and frequency range.…”

mentioning

confidence: 99%

Substrate Roughness Speeds Up Segmental Dynamics of Thin Polymer Films

et al. 2020

View full text Add to dashboard Cite

We show that the segmental mobility of thin films of poly(4-chlorostyrene) prepared under nonequilibrium conditions gets enhanced in the proximity of rough substrates. This trend is in contrast to existing treatments of roughness which conclude it is a source of slower dynamics, and to measurements of thin films of poly(2-vinylpiridine), whose dynamics is roughness invariant. Our experimental evidence indicates the faster interfacial dynamics originate from a reduction in interfacial density, due to the noncomplete filling of substrate asperities. Importantly, our results agree with the same scaling that describes the density dependence of bulk materials, correlating segmental mobility to a term exponential in the specific volume, and with empirical relations linking an increase in glass transition temperature to larger interfacial energy.

show abstract

Comparative XPS Study of Copper, Nickel, and Aluminum Coatings on Polymer Surfaces

Cited by 50 publications

References 28 publications

Enhancement of Thermal Boundary Conductance of Metal–Polymer System

Enhancement of Thermal Boundary Conductance of Metal–Polymer System

Glassy dynamics of soft matter under 1D confinement: How irreversible adsorption affects molecular packing, mobility gradients and orientational polarization in thin films

Substrate Roughness Speeds Up Segmental Dynamics of Thin Polymer Films

Contact Info

Product

Resources

About