TY - JOUR
T1 - Computational investigation into the mechanisms of UV ablation of poly(methyl methacrylate)
AU - Prasad, Manish
AU - Conforti, Patrick F.
AU - Garrison, Barbara J.
AU - Yingling, Yaroslava G.
N1 - Funding Information:
This work was supported by the National Science Foundation through the Information Technology Research Program and the US Air Force Office of Scientific Research through the Multi-University Research Initiative. The computer support was provided by the Academic Services and Emerging Technologies at Penn State University.
PY - 2007/5/30
Y1 - 2007/5/30
N2 - Molecular dynamics simulations with an embedded Monte Carlo based reaction scheme were used to study UV ablation of poly(methyl methacrylate) (PMMA) at 157 nm. We discuss the onset of ablation, the formation and distribution of products in the plume and stress relaxation of the polymer matrix. Laser induced heating and bond-breaks are considered as ablation pathways. We show here that depending on the nature of energy deposition the evolution of ablation plume and yield composition can be quite different. If all of photon energy is converted to heat it can set off ablation via mechanical failure of the material in the heated region. Alternatively, if the photon energy goes towards breaking bonds first, it initiates chemical reactions, polymer unzipping and formation of gaseous products inside the substrate. The ejection of these molecules has a hollowing out effect on the substrate which can lead to ejection of larger chunks. No excessive pressure buildup due to creation of gaseous molecules or entrainment of larger polymer chunks is observed in this case.
AB - Molecular dynamics simulations with an embedded Monte Carlo based reaction scheme were used to study UV ablation of poly(methyl methacrylate) (PMMA) at 157 nm. We discuss the onset of ablation, the formation and distribution of products in the plume and stress relaxation of the polymer matrix. Laser induced heating and bond-breaks are considered as ablation pathways. We show here that depending on the nature of energy deposition the evolution of ablation plume and yield composition can be quite different. If all of photon energy is converted to heat it can set off ablation via mechanical failure of the material in the heated region. Alternatively, if the photon energy goes towards breaking bonds first, it initiates chemical reactions, polymer unzipping and formation of gaseous products inside the substrate. The ejection of these molecules has a hollowing out effect on the substrate which can lead to ejection of larger chunks. No excessive pressure buildup due to creation of gaseous molecules or entrainment of larger polymer chunks is observed in this case.
UR - http://www.scopus.com/inward/record.url?scp=34247630057&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34247630057&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2007.01.054
DO - 10.1016/j.apsusc.2007.01.054
M3 - Article
AN - SCOPUS:34247630057
SN - 0169-4332
VL - 253
SP - 6382
EP - 6385
JO - Applied Surface Science
JF - Applied Surface Science
IS - 15
ER -