Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Investigating the created microstructures and the induced changes in optical properties of PMMA by irradiation of a CO2 laser

Document Type : Research Paper

Authors

S. Sohrabi 1
M. Vesal 1
H. Pazokian 2
M. Mollabashi 1
M. R. Rashidian Vaziri 2

1 Atomic and Molecular Group, Department of Physics, Iran University of Science and Technology, P.O.Box: 16846-13114, Tehran – Iran

2 Photonics and Quantum Technologies Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 14399511-13, Tehran – Iran

https://doi.org/10.24200/nst.2021.1201
Abstract
Laser irradiation of polymers leads to the change of structural and optical properties. Because of its favorable features like cheapness and biocompatibility, poly (methyl methacrylate) (PMMA) is one of those polymers that is in widespread use in different areas such as manufacturing medial microfluidic devices. The aim of the present study is to investigate the effects of the pulse number and the above-threshold fluences of the CO2 laser in the creation of microstructures on the surface of PMMA polymer and variation of its optical properties, like absorption coefficient, refractive index, and bandgap energy. The obtained results indicate the formation of microstructures on the PMMA surface at the above-threshold fluences of the CO2 laser. At a fixed fluence, the density and width of the microstructures increase and decrease by increasing the number of incident pulses, respectively. By increasing the fluence at a fixed number of incident pulses the same trend forms in the microstructures. In the range of investigated fluences in this study, between 10-50 J/cm2, the width of the microstructures is measured to be between 10-15 micrometers. Consistent with previous experimental results, the results of this study indicate the enhancement of absorption coefficient, bandgap, and refractive index of the PMMA polymer after interaction with the CO2 laser.

Highlights

1.    H. Niino and A. Yabe, Excimer laser ablation of polyethersulfone derivatives: periodic morphological micro-modification on ablated surface, J. Photochem. Photobiol. A 65, 303 (1992).

 

2.  Y. Novis et al., Structural origin of surface morphological modifications developed on poly (ethylene terephthalate) by excimer laser photoablation, J. Appl. Phys. 64, 365 (1988).

 

3.   D. Qi et al., Investigations of morphology and formation mechanism of laser-induced annular/droplet-like structures on SiGe film, Opt. Express 21, 9923 (2013).

 

4.     E. Rebollar et al., Assessment of femtosecond laser induced periodic surface structures on polymer films, Phys. Chem. Chem. Phys. 15, 11287  (2013).

 

5.   T. Bahners and E. Schollmeyer, Morphological changes of the surface structure of polymers due to excimer laser radiation: a synergetic effect?, J. Appl. Phys. 66, 1884 (1989).

 

 6.   A. M. Beigzadeh, M. R. Rashidian Vaziri and F. Ziaie, Application of double-exposure digital holographic interferometry method for calculating the absorbed dose in poly (methyl methacrylate) environment. Iranian Journal of Radiation Safety and Measurement 5, 51 (2017).

 

7.    W. Zhang et al., PMMA/PDMS valves and pumps for disposable microfluidics, Lab Chip 9, 3088 (2009).

 

8.   T. F. Hong et al., Rapid prototyping of PMMA microfluidic chips utilizing a CO2 laser, Microfluidic nanofluidics 9, 1125 (2010).

 

 9.   C. Matellan and E. Armando, Cost-effective rapid prototyping and assembly of poly (methyl methacrylate) microfluidic devices, ‌Sci. Rep. 8, 1 (2018).

 

10.   M. Benton et al., Effect of process parameters and material properties on laser micromachining of microchannels, Micromachines 10, 123 (2019).

 

11.   Z. Hu, X. Chen and Y. Ren, A study on the surface qualities of four polymer substrate microchannels using CO2 Laser for microfluidic chip, Surf. Rev. Lett. 26, 1850160 (2019).

 

 12.  A. M. Varsi and A. H. Shaikh, Experimental and statistical study on kerf taper angle during CO2 laser cutting of thermoplastic material, J. Laser Appl. 31, 032010 (2019).

 

13.   M. Tweedie and P. D. Maguire, Microfluidic ratio metering devices fabricated in PMMA by CO2 laser, Microsyst. Technol. 27, 47 (2021).

 

‌14. A. Banejad et al., Design, fabrication and experimental characterization of whole-thermoplastic microvalves and micropumps having micromilled liquid channels of rectangular and half-elliptical cross-sections, Sens. Actuators, A 301, 111713 (2020).

 

15.  Z. Strike, K. Ghofrani and C. Backhouse, CO2 Laser-based rapid prototyping of micropumps, Micromachines 9, 215 (2018).

 

16.  ‌Y. Fan et al., Low-cost PMMA-based microfluidics for the visualization of enhanced oil recovery, Oil Gas Sci. Technol. 73, 26 (2018).

 

17.   S. Dadbin, Surface modification of LDPE film by CO2 pulsed laser irradiation, Eur. Polym. J. 38, 2489 (2002).

 

‌18. Z. L. Hu and X. Y. Chen, Fabrication of polyethylene terephthalate microfluidic chip using CO2 laser system, Int. Polym. Process 33, 106 (2018).

 

19. S. Prakash and S. Kumar, Experimental investigations and analytical modeling of multi-pass CO2 laser processing on PMMA, Precis. Eng. 49, 220 (2017).

 

20.   S. Sohrabi et al., The influence of pulsed CO2 laser irradiation on the optical properties of PMMA: Physics, IJFPS 8, 74 (2018).

 

‌21.   D. Psaltis, S. R. Quake and C. Yang, Developing optofluidic technology through the fusion of microfluidics and optics, nature 442, 381 (2006).

 

22. H. Pazokian et al., Fabrication of multiscale structures on polymethylmethacrylate following pulsed CO2 laser irradiation, Opt. Eng. 57, 125103 (2018).

 

‌23. L. Velardi et al., Modification of polymer characteristics by laser and ion beam, Radiat. Eff. Defects Solids 165, 637 (2010).

 

‌24.   D. G. Waugh and J. Lawrence, On the use of CO2 laser induced surface patterns to modify the wettability of poly (methyl methacrylate)(PMMA), Opt. Lasers Eng. 48, 707 (2010).

 

25. K. L. Mittal, Polymer surface modification: relevance to adhesion Vol. 3., 1st ed., (CRC Press, USA, 2004).

 

26.  N. S. Kasalkova et al., in: Wettability and other surface properties of modified polymers, edited by M. Aliofkhazraei (IntechOpen, 2015), pp. 323-356.

 

‌27.  ‌S. Prakash and S. Kumar, Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask, Opt Laser Technol. 94, 180 (2017).

 

28.  S. Zhang and Y. C. Shin, Effective methods for fabricating trapezoidal shape microchannel of arbitrary dimensions on polymethyl methacrylate (PMMA) substrate by a CO2 laser, Int. J. Adv. Manuf. Technol. 93, 1079 (2017).

 

29. T. Wu, C. Ke and Y. Wang, Fabrication of trapezoidal cross-sectional microchannels on PMMA with a multi-pass translational method by CO2 laser, Optik 183, 953 (2019).

 

30.  T. Lippert, Interaction of photons with polymers: From surface modification to ablation, Plasma Process Polym. 2, 525 (2005).

 

31.   K. P. Lu, S. Lee and C. P. Cheng, Transmittance in irradiated poly (methyl methacrylate) at elevated temperatures, J. Appl. Phys. 88, 5022 (2000).

 

‌32.  V. Rai, C. Mukherjee and B. Jain, UV-Vis and FTIR spectroscopy of gamma irradiated polymethyl methacrylate, Indian J. Pure Appl. Phys. 55, 775 (2017).

 

‌33.  V. Ravindrachary et al., Optical and microstructural studies on electron irradiated PMMA: A positron annihilation study, Polym. Degrad. Stab. 95, 1083 (2010).

 

34.   U. H. Hossain et al., On-line and post irradiation analysis of swift heavy ion induced modification of PMMA (polymethyl-methacrylate), Nucl. Instrum. Methods Phys. Res. B 326, 135 (2014).

 

‌35. M. Falahati et al., Design, modelling and construction of a continuous nuclear gauge for measuring the fluid levels, J. Instrum. 13, P02028 (2018).

 

‌36. M. Zeinali et al., Study of nonlinear optical properties of TiO2–polystyrene nanocomposite films, Quantum Electron. 49, 951 (2019).

 

‌37.   J. R. Alisha et al., In: AIP Conference Proceedings (American Institute of Physics, Vol. 1447, No. 1, USA, 2012) pp. 237-238.

 

‌‌38.  P. Fabbri and M. Messori, In: Modification of polymer properties, edited by C. F. Jasso-Gastin. (William Andrew Publishing, 2017), pp. 109-130.

 

39.  M. R. Rashidian Vaziri et al., Investigating the extrinsic size effect of palladium and gold spherical nanoparticles, Opt. Mater. 64, 413 (2017).

 

40.  V. Kholodovych and W. J. Welsh, In: Physical properties of polymers handbook, edited by J. E. Mark. (Springer, New York, 2007), pp. 611-617.

 

41. H. Pazokian et al., Formation of different microstructures on a polyethersulfone film following XeCl laser irradiation, Iran. J. Phys. Res. 14, 47 (2014).

 

‌42.  F. Languyet et al., Flat Fresnel doublets made of PMMA and PC: combining low cost production and very high concentration ratio for CPV, Opt. Express 19, A280 (2011).

 

‌43.   G. Beadie et al., Refractive index measurements of poly (methyl methacrylate) (PMMA) from 0.4–1.6 μm, Appl. opt. 54, F139 (2015).

Keywords

Microstructures
PMMA polymer
Laser ablation
Pulsed CO2 laser
1.    H. Niino and A. Yabe, Excimer laser ablation of polyethersulfone derivatives: periodic morphological micro-modification on ablated surface, J. Photochem. Photobiol. A 65, 303 (1992).
 
2.  Y. Novis et al., Structural origin of surface morphological modifications developed on poly (ethylene terephthalate) by excimer laser photoablation, J. Appl. Phys. 64, 365 (1988).
 
3.   D. Qi et al., Investigations of morphology and formation mechanism of laser-induced annular/droplet-like structures on SiGe film, Opt. Express 21, 9923 (2013).
 
4.     E. Rebollar et al., Assessment of femtosecond laser induced periodic surface structures on polymer films, Phys. Chem. Chem. Phys. 15, 11287  (2013).
 
5.   T. Bahners and E. Schollmeyer, Morphological changes of the surface structure of polymers due to excimer laser radiation: a synergetic effect?, J. Appl. Phys. 66, 1884 (1989).
 
 6.   A. M. Beigzadeh, M. R. Rashidian Vaziri and F. Ziaie, Application of double-exposure digital holographic interferometry method for calculating the absorbed dose in poly (methyl methacrylate) environment. Iranian Journal of Radiation Safety and Measurement 5, 51 (2017).
 
7.    W. Zhang et al., PMMA/PDMS valves and pumps for disposable microfluidics, Lab Chip 9, 3088 (2009).
 
8.   T. F. Hong et al., Rapid prototyping of PMMA microfluidic chips utilizing a CO2 laser, Microfluidic nanofluidics 9, 1125 (2010).
 
 9.   C. Matellan and E. Armando, Cost-effective rapid prototyping and assembly of poly (methyl methacrylate) microfluidic devices, ‌Sci. Rep. 8, 1 (2018).
 
10.   M. Benton et al., Effect of process parameters and material properties on laser micromachining of microchannels, Micromachines 10, 123 (2019).
 
11.   Z. Hu, X. Chen and Y. Ren, A study on the surface qualities of four polymer substrate microchannels using CO2 Laser for microfluidic chip, Surf. Rev. Lett. 26, 1850160 (2019).
 
 12.  A. M. Varsi and A. H. Shaikh, Experimental and statistical study on kerf taper angle during CO2 laser cutting of thermoplastic material, J. Laser Appl. 31, 032010 (2019).
 
13.   M. Tweedie and P. D. Maguire, Microfluidic ratio metering devices fabricated in PMMA by CO2 laser, Microsyst. Technol. 27, 47 (2021).
 
‌14. A. Banejad et al., Design, fabrication and experimental characterization of whole-thermoplastic microvalves and micropumps having micromilled liquid channels of rectangular and half-elliptical cross-sections, Sens. Actuators, A 301, 111713 (2020).
 
15.  Z. Strike, K. Ghofrani and C. Backhouse, CO2 Laser-based rapid prototyping of micropumps, Micromachines 9, 215 (2018).
 
16.  ‌Y. Fan et al., Low-cost PMMA-based microfluidics for the visualization of enhanced oil recovery, Oil Gas Sci. Technol. 73, 26 (2018).
 
17.   S. Dadbin, Surface modification of LDPE film by CO2 pulsed laser irradiation, Eur. Polym. J. 38, 2489 (2002).
 
‌18. Z. L. Hu and X. Y. Chen, Fabrication of polyethylene terephthalate microfluidic chip using CO2 laser system, Int. Polym. Process 33, 106 (2018).
 
19. S. Prakash and S. Kumar, Experimental investigations and analytical modeling of multi-pass CO2 laser processing on PMMA, Precis. Eng. 49, 220 (2017).
 
20.   S. Sohrabi et al., The influence of pulsed CO2 laser irradiation on the optical properties of PMMA: Physics, IJFPS 8, 74 (2018).
 
‌21.   D. Psaltis, S. R. Quake and C. Yang, Developing optofluidic technology through the fusion of microfluidics and optics, nature 442, 381 (2006).
 
22. H. Pazokian et al., Fabrication of multiscale structures on polymethylmethacrylate following pulsed CO2 laser irradiation, Opt. Eng. 57, 125103 (2018).
 
‌23. L. Velardi et al., Modification of polymer characteristics by laser and ion beam, Radiat. Eff. Defects Solids 165, 637 (2010).
 
‌24.   D. G. Waugh and J. Lawrence, On the use of CO2 laser induced surface patterns to modify the wettability of poly (methyl methacrylate)(PMMA), Opt. Lasers Eng. 48, 707 (2010).
 
25. K. L. Mittal, Polymer surface modification: relevance to adhesion Vol. 3., 1st ed., (CRC Press, USA, 2004).
 
26.  N. S. Kasalkova et al., in: Wettability and other surface properties of modified polymers, edited by M. Aliofkhazraei (IntechOpen, 2015), pp. 323-356.
 
‌27.  ‌S. Prakash and S. Kumar, Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask, Opt Laser Technol. 94, 180 (2017).
 
28.  S. Zhang and Y. C. Shin, Effective methods for fabricating trapezoidal shape microchannel of arbitrary dimensions on polymethyl methacrylate (PMMA) substrate by a CO2 laser, Int. J. Adv. Manuf. Technol. 93, 1079 (2017).
 
29. T. Wu, C. Ke and Y. Wang, Fabrication of trapezoidal cross-sectional microchannels on PMMA with a multi-pass translational method by CO2 laser, Optik 183, 953 (2019).
 
30.  T. Lippert, Interaction of photons with polymers: From surface modification to ablation, Plasma Process Polym. 2, 525 (2005).
 
31.   K. P. Lu, S. Lee and C. P. Cheng, Transmittance in irradiated poly (methyl methacrylate) at elevated temperatures, J. Appl. Phys. 88, 5022 (2000).
 
‌32.  V. Rai, C. Mukherjee and B. Jain, UV-Vis and FTIR spectroscopy of gamma irradiated polymethyl methacrylate, Indian J. Pure Appl. Phys. 55, 775 (2017).
 
‌33.  V. Ravindrachary et al., Optical and microstructural studies on electron irradiated PMMA: A positron annihilation study, Polym. Degrad. Stab. 95, 1083 (2010).
 
34.   U. H. Hossain et al., On-line and post irradiation analysis of swift heavy ion induced modification of PMMA (polymethyl-methacrylate), Nucl. Instrum. Methods Phys. Res. B 326, 135 (2014).
 
‌35. M. Falahati et al., Design, modelling and construction of a continuous nuclear gauge for measuring the fluid levels, J. Instrum. 13, P02028 (2018).
 
‌36. M. Zeinali et al., Study of nonlinear optical properties of TiO2–polystyrene nanocomposite films, Quantum Electron. 49, 951 (2019).
 
‌37.   J. R. Alisha et al., In: AIP Conference Proceedings (American Institute of Physics, Vol. 1447, No. 1, USA, 2012) pp. 237-238.
 
‌‌38.  P. Fabbri and M. Messori, In: Modification of polymer properties, edited by C. F. Jasso-Gastin. (William Andrew Publishing, 2017), pp. 109-130.
 
39.  M. R. Rashidian Vaziri et al., Investigating the extrinsic size effect of palladium and gold spherical nanoparticles, Opt. Mater. 64, 413 (2017).
 
40.  V. Kholodovych and W. J. Welsh, In: Physical properties of polymers handbook, edited by J. E. Mark. (Springer, New York, 2007), pp. 611-617.
 
41. H. Pazokian et al., Formation of different microstructures on a polyethersulfone film following XeCl laser irradiation, Iran. J. Phys. Res. 14, 47 (2014).
 
‌42.  F. Languyet et al., Flat Fresnel doublets made of PMMA and PC: combining low cost production and very high concentration ratio for CPV, Opt. Express 19, A280 (2011).
 
‌43.   G. Beadie et al., Refractive index measurements of poly (methyl methacrylate) (PMMA) from 0.4–1.6 μm, Appl. opt. 54, F139 (2015).

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