Reactive species in atmospheric pressure plasma beams

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Ernest Phelps
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2 Reactive species in atmospheric pressure plasma beams Dirk Pasedag Institute of Physics Ernst-Moritz Moritz-Arndt-University Greifswald, Germany Graduate Summer Institute Comple Plasmas Stevens Institute of Technology, Hoboken,, J (USA) August

Atmospheric pressure plasma beams high technological potential for surface treatment in-line capabilities at low costs due to avoiding epensive vacuum systems used in many kinds of industry

3 Atmospheric pressure plasma beams high technological potential for surface treatment in-line capabilities at low costs due to avoiding epensive vacuum systems used in many kinds of industry automotive packaging computer cleaning, activation, functionalization, deposition strongly improoved conditions for laquer bonding and printig of polymer surfaces Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August I

4 Atmospheric pressure plasma beams high technological potential for surface treatment in-line capabilities at low costs due to avoiding epensive vacuum systems used in many kinds of industry automotive packaging computer cleaning, activation, functionalization, deposition strongly improoved conditions for laquer bonding and printig of polymer surfaces FRAUHFER - Institute for Manufacturing Engineering and Applied Materials Research in Bremen, GER Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August I

5 utline ES BEAM T GAS T RT [] CHEMISTRY * (A) H H-RADICALS SURFACE TREATMET THERMAL PRBE Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August II

6 The investigated beam power supply: active region U = 8 kv pp f = 1, ,7 khz gas supply: dried ambient air synthetic air nitrogen miture of + (argon, oygen) afterglow region (plasma beam) gas flow rate: D = 5 sl/min Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August III

7 Identification of the yellow afterglow as a continuum of ecited molecules ES and plasma chemistry Intensity [arb.u.] H λ [nm] active plasma afterglow continuum Intensity [arb.u.] Sutohet et al. al * + + M + M * + hν continuum Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August IV

8 ES and plasma chemistry different gases (Air,, - miture) + e ( C) + e ( C) ( B) + hν. pos. Syst. Intensity [a.u.] γ nd pos. syst. distance from the HV electrode 0,0-0,5 mm Intensity [a.u.] nd pos. syst. distance from the HV electrode 0,0-0,5 mm λ [nm] λ [nm] + + no γ emission + e (A ) ( A) + ( A) + γ Syst. + e + + e + e ( A ) + e Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August V

Temperatures in the beam distanze from the nozzle outlet X [mm] Intensität [arb.u.] 0 4 6 8. pos. syst. (0-0)-trans.

[%] (0-0)-transition of the SPS of rotational temperature T R variation of T R = 500 5500 K (± 50 K) relation: T Gas T R T ν T e 334 λ 336 [nm] 338

9 Temperatures in the beam distanze from the nozzle outlet X [mm] Intensität [arb.u.] pos. syst. (0-0)-trans λ [nm] nm periodet [µs] rel.int. [%] (0-0)-transition of the SPS of rotational temperature T R variation of T R = K (± 50 K) relation: T Gas T R T ν T e 334 λ 336 [nm] 338 spatio-temporal resolved measurements gas velocity v = 10 ms -1 velocity of the beam confirming with continuity equation at T = 1100 K Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August VI

10 * + + M + I contin ygen atom density first rough estimation γ 1 γ1[ ][ ][ M M (chemo luminescence reaction) continuum ] if [][M] = const. I contin [] n ()/n (0) 1,0 0,8 0,6 0,4 0, T Gas = 1100 K T Gas = 900 K Intensity decay of the Continuum 0, distance from nozzle [mm] 1,0 0,8 0,6 0,4 0, 0,0 Intensity [a.u.] dominating process: γ + M + n n + Diff.Equ.: ( ) (0) dn dt = α M = γ n ; α n T 1,4 Gas n (0) Upper limit for the amount of oygen atoms 10 Vol.% Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August VII

11 Step to a more comple kinetics d d 1 = ( k n v 1 k 6 n + ( A) k n 1 γ n + k 4 n γ n ( A) γ n 3 ) d d d d k6n ( A) + γ n kn γ 3n = ( k n v 1 n ( A) k1n kn γ n γ 4n = ( k v 6 ) ) (A) d d ( A) 1 = ( k v 3 n ( A) k 6 n ( A) k 4 n ( A) k 5 n ( A) ) Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August VIII

12 X i E-3 1E-4 1E-5 1E-6 umerical calculation - FACSIMILE I Cont 3 T Gas constant = T Gas () distance from nozzle [mm] γ1[ ][ ][ M] Intensity [norm.] * [] = 10 Vol% * [] = 5 Vol% * [] = 0,5 Vol% Intensity of the continuum distance from nozzle [mm] X *X [norm.] amount of -atoms at the nozzle outlet in the percent range - [] between 5 and 10 Vol.% Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August IX

13 Intensity [a.u.] Intensity [arb.u.] H + e H( X ) + H + e H (R-branch) H (P-branch) admiture: 30 sccm 15 sccm 5 sccm 0 sccm synthetic air λ [nm ] H - radicals dried ambient air synthetic air gas flow: 5 sl/min ( admiture < 0,1 % ) admiture H (g) [sccm/min] ; H ( X) + e H( A) + e H (R-branch) H (P-branch) H ( X ) + h ν admiture: 30 sccm 15 sccm 5 sccm 0 sccm ambient air λ [nm ] Activation of polyethylene PE - substrates: PE substrat activation: Surface energy [m/m] without referenz dry 44 wet 51 CA - contactangle measurements Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August X

[ at.-%] XPS [at.[ at.-%] reference 93,3 30, 0,5 9,1 3,0 <0,1 air plasma 1,6 67,5 1,9 14,3 1,4 3,3 nitrogen

14 nitrogen Treatment of Polyethylene (PE) - substrates air XPS spectra of 1S XPS: H 3, R-C XPS:, 3 1s peak shift PE-treatment contact angle CA water [ ] surface tension [m/m] lap shear strength [Mpa] AFM RMS roughness [nm] [at.[ at.-%] XPS [at.[ at.-%] reference 93,3 30, 0,5 9,1 3,0 <0,1 air plasma 1,6 67,5 1,9 14,3 1,4 3,3 nitrogen plasma 41,0 55,3,1 11,0 16,9 5,4 Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August XI

Thermal probe - basics T heat h3 ( t ) = h + h (1 e 1 t ) Q out Q in 5 mm temperature T cool c 3 ( t ) = c + c ( e 1 t calibration by LASER ) H p thermal probe dq in /dt = dh /dt p + dq out /dt time

15 Thermal probe - basics T heat h3 ( t ) = h + h (1 e 1 t ) Q out Q in 5 mm temperature T cool c 3 ( t ) = c + c ( e 1 t calibration by LASER ) H p thermal probe dq in /dt = dh /dt p + dq out /dt time dh p /dt = m c (dt p / dt) Heating phase: (plasma on) dh p /dt (heat) = dq in /dt - dq dq out /dt Cooling phase: (plasma off) Q in = 0 dh p /dt (cool) = - dq dq out /dt dq in /dt =m c [dtdt p /dt (heat) - dt p /dt dq in /dt ] (cool) Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August XII

16 Thermal probe measurements - aial temperature [ C] 400 variation of with = mm energy flu [W/cm ] dried ambient air time t [s] distance from the nozzle [mm] etrapolation of this curve towards the nozzle outlet would lead to an energy flu to the probe between 80 and 100 W/cm (thermal energie of the gases at T = 1100 K E th = 500 W) Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August XIII

17 temperature [ C] r - variation r = 0,5mm Thermal probe measurements - radial time t [s] energy flu [W/cm ] ,5 W/cm area: 14,9 W/cm ambient air radial distance r [cm] energy flu [W/cm ] with mod.-substrate without mod.-substrate radial distance r [cm] energy flu [W/cm ] ,4 W/cm area: 4,7 W/cm ambient air (substrate) radial distance r [cm] Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August XIV

18 Summary - onthermal,, hot plasma (T G 1100 K ; T R K ; T e 10 5 K) - Recombination processes in the relaing beam yellow glow : Indicator for -atoms - -atom density: : [] 5 Vol.% - Gasflow velocity: : v = 10 m/s at D=5 sl/min - Admiture of water vapour H-emission higher free surface energies on activated PE-substrates - Energy transfer to surface in order of 10 W/cm high substrate velocities in treatment Dirk Pasedag - University Greifswald Graduate Summer School - Hoboken J, August XV

19 Thank You for Your attention!

Energy fluxes in plasmas for fabrication of nanostructured materials

Energy fluxes in plasmas for fabrication of nanostructured materials IEAP, Universität Kiel 2nd Graduate Summer Institute "Complex Plasmas" August 5-13, 2010 in Greifswald (Germany) AG 1 Outline Motivation