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Hennekam BE, Al‐Bataineh SA, Michelmore A. Fabrication and characterization of biorenewable plasma polymer films using sandalwood oil precursor. J Appl Polym Sci 2020. [DOI: 10.1002/app.49288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Brent E. Hennekam
- School of Natural Built EnvironmentsUniversity of South Australia Mawson Lakes South Australia Australia
| | - Sameer A. Al‐Bataineh
- Future Industries InstituteUniversity of South Australia Mawson Lakes South Australia Australia
| | - Andrew Michelmore
- Future Industries InstituteUniversity of South Australia Mawson Lakes South Australia Australia
- School of EngineeringUniversity of South Australia Mawson Lakes South Australia Australia
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Saboohi S, Jasieniak M, Coad BR, Griesser HJ, Short RD, Michelmore A. Comparison of Plasma Polymerization under Collisional and Collision-Less Pressure Regimes. J Phys Chem B 2015; 119:15359-69. [PMID: 26567805 DOI: 10.1021/acs.jpcb.5b07309] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While plasma polymerization is used extensively to fabricate functionalized surfaces, the processes leading to plasma polymer growth are not yet completely understood. Thus, reproducing processes in different reactors has remained problematic, which hinders industrial uptake and research progress. Here we examine the crucial role pressure plays in the physical and chemical processes in the plasma phase, in interactions at surfaces in contact with the plasma phase, and how this affects the chemistry of the resulting plasma polymer films using ethanol as the gas precursor. Visual inspection of the plasma reveals a change from intense homogeneous plasma at low pressure to lower intensity bulk plasma at high pressure, but with increased intensity near the walls of the chamber. It is demonstrated that this occurs at the transition from a collision-less to a collisional plasma sheath, which in turn increases ion and energy flux to surfaces at constant RF power. Surface analysis of the resulting plasma polymer films show that increasing the pressure results in increased incorporation of oxygen and lower cross-linking, parameters which are critical to film performance. These results and insights help to explain the considerable differences in plasma polymer properties observed by different research groups using nominally similar processes.
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Affiliation(s)
- Solmaz Saboohi
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
| | - Marek Jasieniak
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
| | - Bryan R Coad
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
| | - Hans J Griesser
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
| | - Robert D Short
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
| | - Andrew Michelmore
- Mawson Institute, and ‡School of Engineering, University of South Australia , Mawson Lakes Campus, Mawson Lakes, Australia 5095
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Michelmore A, Charles C, Boswell RW, Short RD, Whittle JD. Defining plasma polymerization: new insight into what we should be measuring. ACS APPLIED MATERIALS & INTERFACES 2013; 5:5387-5391. [PMID: 23758848 DOI: 10.1021/am401484b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
External parameters (RF power and precursor flow rate) are typically quoted to define plasma polymerization experiments. Utilizing a parallel-plate electrode reactor with variable geometry, it is shown that these parameters cannot be transferred to reactors with different geometries in order to reproduce plasma polymer films using four precursors. Measurements of ion flux and power coupling efficiency confirm that intrinsic plasma properties vary greatly with reactor geometry at constant applied RF power. It is further demonstrated that controlling intrinsic parameters, in this case the ion flux, offers a more widely applicable method of defining plasma polymerization processes, particularly for saturated and allylic precursors.
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Affiliation(s)
- Andrew Michelmore
- Mawson Institute, University of South Australia, Mawson Lakes Campus, 5095, Adelaide, Australia.
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Michelmore A, Steele DA, Whittle JD, Bradley JW, Short RD. Nanoscale deposition of chemically functionalised films via plasma polymerisation. RSC Adv 2013. [DOI: 10.1039/c3ra41563e] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Michelmore A, Bryant PM, Steele DA, Vasilev K, Bradley JW, Short RD. Role of positive ions in determining the deposition rate and film chemistry of continuous wave hexamethyl disiloxane plasmas. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:11943-11950. [PMID: 21863814 DOI: 10.1021/la202010n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
New data shed light on the mechanisms of film growth from low power, low pressure plasmas of organic compounds. These data rebalance the widely held view that plasma polymer formation is due to radical/neutral reactions only and that ions play no direct role in contributing mass at the surface. Ion reactions are shown to play an important role in both the plasma phase and at the surface. The mass deposition rate and ion flux in continuous wave hexamethyl disiloxane (HMDSO) plasmas have been studied as a function of pressure and applied RF power. Both the deposition rate and ion flux were shown to increase with applied power; however, the deposition rate increased with pressure while the ion flux decreased. Positive ion mass spectrometry of the plasma phase demonstrates that the dominant ionic species is the (HMDSO-CH(3))(+) ion at m/z 147, but significant fragmentation and subsequent oligomerization was also observed. Chemical analysis of the deposits by X-ray photoelectron spectroscopy and secondary ion mass spectrometry show that the deposits were consistent with deposits reported by previous workers grown from plasma and hyperthermal (HMDSO-CH(3))(+) ions. Increasing coordination of silicon with oxygen in the plasma deposits reveals the role of ions in the growth of plasma polymers. Comparing the calculated film thicknesses after a fixed total fluence of 1.5 × 10(19) ions/m(2) to results for hyperthermal ions shows that ions can contribute significantly to the total absorbed mass in the deposits.
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Affiliation(s)
- Andrew Michelmore
- Mawson Institute, University of South Australia, Mawson Lakes, SA 5095 Adelaide, Australia.
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Swindells I, Voronin SA, Bryant PM, Alexander MR, Bradley JW. Temporal Evolution of an Electron-Free Afterglow in the Pulsed Plasma Polymerisation of Acrylic Acid. J Phys Chem B 2008; 112:3938-47. [DOI: 10.1021/jp7104117] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ian Swindells
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom, and The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Sergey A. Voronin
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom, and The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Paul M. Bryant
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom, and The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Morgan R. Alexander
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom, and The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - James W. Bradley
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom, and The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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Voronin SA, Zelzer M, Fotea C, Alexander MR, Bradley JW. Pulsed and Continuous Wave Acrylic Acid Radio Frequency Plasma Deposits: Plasma and Surface Chemistry. J Phys Chem B 2007; 111:3419-29. [PMID: 17388498 DOI: 10.1021/jp068488z] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Plasma polymers have been formed from acrylic acid using a pulsed power source. An on-pulse duration of 100 micros was used with a range of discharge off-times between 0 (continuous wave) and 20,000 micros. X-ray photoelectron spectroscopy (XPS) has been used in combination with trifluoroethanol (TFE) derivatization to quantify the surface concentration of the carboxylic acid functionality in the deposit. Retention of this functionality from the monomer varied from 2% to 65%. When input power was expressed as the time-averaged energy per monomer molecule, E(mean), the deposit chemistry achieved could be described using a single relationship for all deposition conditions. Deposition rates were monitored using a quartz crystal microbalance, which revealed a range from 20 to 200 microg m(-2) s(-1), and these fell as COOH functional retention increased. The flow rate was found to be the major determinant of the deposition rate, rather than being uniquely defined by E(mean), connected to the rate at which fresh monomer enters the system in the monomer deficient regime. The neutral species were collected in a time-averaged manner. As the energy delivered per molecule in the system (E(mean)) decreased, the amount of intact monomer increased, with the average neutral mass approaching 72 amu as E(mean) tends to zero. No neutral oligomeric species were detected. Langmuir probes have been used to determine the temporal evolution of the density and temperature of the electrons in the plasma and the plasma potential adjacent to the depositing film. It has been found that even 500 micros into the afterglow period that ionic densities are still significant, 5-10% of the on-time density, and that ion accelerating sheath potentials fall from 40 V in the on-time to a few volts in the off-time. We have made the first detailed, time- and energy-resolved mass spectrometry measurements in depositing acrylic acid plasma. These have allowed us to identify and quantify the positive ion species in the acrylic acid plasma during both the on- and the off- periods. The relative intensities of oligomeric species of the type [nM + H]+ as large as n = 3 were observed to increase in the off-time suggesting vapor phase polymerization after power input to the plasma was ceased. The energy distribution functions of these ions demonstrated that they were produced in the plasma in both the on- and the off-times. This remarkable observation contradicts the assumptions usually made when speculating on pulsed plasma that ions have very short lifetimes, although it is anticipated that radicals still have significantly longer lifetimes, estimated from calculation to be in excess of 1 ms. The increase in average positive ion mass during the off-period can be related to the lower mobility of the heavier components, reducing their relative loss to surfaces, and the polymer chain growth in the gas phase due to the ion-neutral collisions. The implications of these observations are discussed in light of polymerization mechanisms proposed from continuous acrylic acid and millisecond pulsing plasmas.
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Affiliation(s)
- Sergey A Voronin
- Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, United Kingdom
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Bullett NA, Talib RA, Short RD, McArthur SL, Shard AG. Chemical and thermo-responsive characterisation of surfaces formed by plasma polymerisation ofN-isopropyl acrylamide. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2318] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Barton D, Shard AG, Short RD, Bradley JW. The Effect of Positive Ion Energy on Plasma Polymerization: A Comparison between Acrylic and Propionic Acids. J Phys Chem B 2005; 109:3207-11. [PMID: 16851342 DOI: 10.1021/jp045338k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Using a novel RF biasing technique, the energy of positive ions at a depositing substrate is controlled, independently of other parameters. Under bias conditions which gave the maximum and minimum ion energies, plasmas of propionic and acrylic acid were investigated using mass spectrometry, an ion flux probe, quartz crystal microbalance, and X-ray photoelectron spectroscopy (XPS). For both compounds investigated, the ion energy affects the deposition rate but leaves the neutral gas-phase chemistry and positive ion fluxes unchanged. The chemistry of the polymer deposit for acrylic acid is unaffected by the change in ion energy, but the chemistry of the propionic acid plasma polymer changes markedly. We argue that the results presented are consistent with the hypothesis that, under the plasma conditions explored, the carbon-carbon double bond present in acrylic acid plays a significant role in the formation of the polymer. Conversely, the absence of this bond in propionic acid leads us to conclude that positive ions contribute significantly to film formation for this compound.
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Affiliation(s)
- David Barton
- Plasso Technology Ltd., The Innovation Centre, 217 Portobello Sheffield S14DP, United Kingdom
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Beck AJ, Candan S, Short RD, Goodyear A, Braithwaite NSJ. The Role of Ions in the Plasma Polymerization of Allylamine. J Phys Chem B 2001. [DOI: 10.1021/jp0043468] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Alison J. Beck
- Laboratory for Surface and Interface Analysis, Department of Engineering Materials, University of Sheffield, Sheffield, U.K. S1 3JD, and The Open University, Oxford Research Unit, Foxcombe Hall, Berkeley Road, Boars Hill, Oxford, U.K. OX1 5HR
| | - Sennur Candan
- Laboratory for Surface and Interface Analysis, Department of Engineering Materials, University of Sheffield, Sheffield, U.K. S1 3JD, and The Open University, Oxford Research Unit, Foxcombe Hall, Berkeley Road, Boars Hill, Oxford, U.K. OX1 5HR
| | - Robert D. Short
- Laboratory for Surface and Interface Analysis, Department of Engineering Materials, University of Sheffield, Sheffield, U.K. S1 3JD, and The Open University, Oxford Research Unit, Foxcombe Hall, Berkeley Road, Boars Hill, Oxford, U.K. OX1 5HR
| | - Alec Goodyear
- Laboratory for Surface and Interface Analysis, Department of Engineering Materials, University of Sheffield, Sheffield, U.K. S1 3JD, and The Open University, Oxford Research Unit, Foxcombe Hall, Berkeley Road, Boars Hill, Oxford, U.K. OX1 5HR
| | - Nick St. J. Braithwaite
- Laboratory for Surface and Interface Analysis, Department of Engineering Materials, University of Sheffield, Sheffield, U.K. S1 3JD, and The Open University, Oxford Research Unit, Foxcombe Hall, Berkeley Road, Boars Hill, Oxford, U.K. OX1 5HR
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