Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores

Mischa Zelzer, David Scurr, Badr Abdullah, Andrew J. Urquhart, Nikilaj Gadegaard, James W. Bradley, Morgan R. Alexander

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Plasma species that form plasma polymer deposits readily penetrate through small openings and are therefore well suited to coat the interior of porous objects. Here, we show how the size of the cross section of square channels influences the penetration of active species from a hexane plasma and how it affects the formation of surface chemical gradients in the interior of these model pores. WCA mapping and ToF-SIMS imaging are used to visualize the plasma polymer deposit in the interior of the model pores and demonstrate that a strong dependence of the wettability gradient profile only exists up to a channel cross section of about 1 mm. XPS data allow us to calculate a deposition rate of plasma polymerized hexane (ppHex) at discrete positions on the surface and show that the deposition rate of ppHex is reduced by the presence of the mask up to a distance of 16 mm in advance of the channel opening. A strong dependence of the ppHex deposition rate on the cross-section of the channels is found within the first 2 mm in front of the pore opening. An estimation of the sheath thickness suggests that this effect can be attributed to the plasma sheath that perturbs the plasma in front of the pores. Plasma mass spectrometry allows us to identify the nature of the plasma species penetrating from the plasma through the pores and shows that no negatively charged ions are able to penetrate through the small channels. Neutral and positively charged species penetrate several millimeters down the channels and both species are therefore likely to contribute to the formation of the deposit on the sample. In addition, the formation of positively charged higher molecular mass hexane fragments is observed in the gas phase, demonstrating the likelihood of neutral-positive reactions in the plasma.
LanguageEnglish
Pages8487-8494
Number of pages7
JournalJournal of Physical Chemistry B
Volume113
Issue number25
DOIs
Publication statusPublished - 2009

Fingerprint

Plasma sheaths
plasma sheaths
Masks
Polymers
masks
porosity
Plasmas
polymers
Hexanes
Hexane
Deposition rates
Deposits
deposits
cross sections
gradients
Molecular mass
Secondary ion mass spectrometry
wettability
sheaths
secondary ion mass spectrometry

Keywords

  • plasma
  • polymers
  • pores
  • physical chemistry
  • pharmacology

Cite this

Zelzer, M., Scurr, D., Abdullah, B., Urquhart, A. J., Gadegaard, N., Bradley, J. W., & Alexander, M. R. (2009). Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores. Journal of Physical Chemistry B, 113(25), 8487-8494. https://doi.org/10.1021/jp902137y
Zelzer, Mischa ; Scurr, David ; Abdullah, Badr ; Urquhart, Andrew J. ; Gadegaard, Nikilaj ; Bradley, James W. ; Alexander, Morgan R. / Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores. In: Journal of Physical Chemistry B. 2009 ; Vol. 113, No. 25. pp. 8487-8494.
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Zelzer, M, Scurr, D, Abdullah, B, Urquhart, AJ, Gadegaard, N, Bradley, JW & Alexander, MR 2009, 'Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores' Journal of Physical Chemistry B, vol. 113, no. 25, pp. 8487-8494. https://doi.org/10.1021/jp902137y

Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores. / Zelzer, Mischa; Scurr, David; Abdullah, Badr; Urquhart, Andrew J.; Gadegaard, Nikilaj; Bradley, James W.; Alexander, Morgan R.

In: Journal of Physical Chemistry B, Vol. 113, No. 25, 2009, p. 8487-8494.

Research output: Contribution to journalArticle

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T1 - Influence of the plasma sheath on plasma polymer deposition in advance of a mask and down pores

AU - Zelzer, Mischa

AU - Scurr, David

AU - Abdullah, Badr

AU - Urquhart, Andrew J.

AU - Gadegaard, Nikilaj

AU - Bradley, James W.

AU - Alexander, Morgan R.

PY - 2009

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N2 - Plasma species that form plasma polymer deposits readily penetrate through small openings and are therefore well suited to coat the interior of porous objects. Here, we show how the size of the cross section of square channels influences the penetration of active species from a hexane plasma and how it affects the formation of surface chemical gradients in the interior of these model pores. WCA mapping and ToF-SIMS imaging are used to visualize the plasma polymer deposit in the interior of the model pores and demonstrate that a strong dependence of the wettability gradient profile only exists up to a channel cross section of about 1 mm. XPS data allow us to calculate a deposition rate of plasma polymerized hexane (ppHex) at discrete positions on the surface and show that the deposition rate of ppHex is reduced by the presence of the mask up to a distance of 16 mm in advance of the channel opening. A strong dependence of the ppHex deposition rate on the cross-section of the channels is found within the first 2 mm in front of the pore opening. An estimation of the sheath thickness suggests that this effect can be attributed to the plasma sheath that perturbs the plasma in front of the pores. Plasma mass spectrometry allows us to identify the nature of the plasma species penetrating from the plasma through the pores and shows that no negatively charged ions are able to penetrate through the small channels. Neutral and positively charged species penetrate several millimeters down the channels and both species are therefore likely to contribute to the formation of the deposit on the sample. In addition, the formation of positively charged higher molecular mass hexane fragments is observed in the gas phase, demonstrating the likelihood of neutral-positive reactions in the plasma.

AB - Plasma species that form plasma polymer deposits readily penetrate through small openings and are therefore well suited to coat the interior of porous objects. Here, we show how the size of the cross section of square channels influences the penetration of active species from a hexane plasma and how it affects the formation of surface chemical gradients in the interior of these model pores. WCA mapping and ToF-SIMS imaging are used to visualize the plasma polymer deposit in the interior of the model pores and demonstrate that a strong dependence of the wettability gradient profile only exists up to a channel cross section of about 1 mm. XPS data allow us to calculate a deposition rate of plasma polymerized hexane (ppHex) at discrete positions on the surface and show that the deposition rate of ppHex is reduced by the presence of the mask up to a distance of 16 mm in advance of the channel opening. A strong dependence of the ppHex deposition rate on the cross-section of the channels is found within the first 2 mm in front of the pore opening. An estimation of the sheath thickness suggests that this effect can be attributed to the plasma sheath that perturbs the plasma in front of the pores. Plasma mass spectrometry allows us to identify the nature of the plasma species penetrating from the plasma through the pores and shows that no negatively charged ions are able to penetrate through the small channels. Neutral and positively charged species penetrate several millimeters down the channels and both species are therefore likely to contribute to the formation of the deposit on the sample. In addition, the formation of positively charged higher molecular mass hexane fragments is observed in the gas phase, demonstrating the likelihood of neutral-positive reactions in the plasma.

KW - plasma

KW - polymers

KW - pores

KW - physical chemistry

KW - pharmacology

UR - http://dx.doi.org/10.1021/jp902137y

U2 - 10.1021/jp902137y

DO - 10.1021/jp902137y

M3 - Article

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SP - 8487

EP - 8494

JO - Journal of Physical Chemistry B

T2 - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 25

ER -