Hi Akanksha,

there is little confusion in your ideas. Your questions are close to answers. But I am not sure what you mean by "He-O plasma irradiation". Did you expose the PET substrates directly to a low-pressure plasma nearby having all species in contact with the substrate? If so, next question is reactor type, electrode arragement, power density, pressure and distance of the PET from the full glow zone. If we assume some barrel-type reactor driven by RF, > 10 W/dm3, 10 Pa and the substrates in the full glow zone, I personally assume that

1. many of the ester groups O-C=O get eliminated as CO2,

2. some of the C-H bonds and few of the C-C bonds of the aromatic rings are cleaved.

3. The resulting radicals will recombine incorporating the oxygen diradicals.

4. ome rearrangement reactions will occur .

I strongly recommend the books:

J.R. Hollahan, A.T.Bell: "Techniques and Applications of Plasma Chemistry"

Brian Chapman: "Glow Discharge Processes"

Bernard Blaustein:"Chemical Reactions in Electrical Discharges"

Best wishes,

Heinrich

Thankyou Dr. Gruenwald. I'll look over the sources too.

Dear Dr. Akanksha Pragya ,

I suggest you to have a look at the following, interesting papers:

-Processing of plasma-modified and polymer- grafted hydrophilic PET surfaces, and study of their aging and bioadhesive properties

Maria Jesus Pérez-Roldán, Dominique Debarnot, Fabienne Poncin

RSC Advances 4(56):31409 (2014)

Available on RG at: https://www.researchgate.net/publication/265382750_Processing_of_plasma-modified_and_polymer-_grafted_hydrophilic_PET_surfaces_and_study_of_their_aging_and_bioadhesive_properties

-Plasma Processing for Tailoring the Surface Properties of Polymers (Chapter)

Hisham M. Abourayana and Denis P. Dowling

Surface Energy, Book ISBN: 978-953-51-2216-6 (2015)

Chapter available at: https://www.intechopen.com/books/surface-energy/plasma-processing-for-tailoring-the-surface-properties-of-polymers

-Surface Properties of PET Polymer Treated by Plasma Immersion Techniques for Food Packaging

Péricles Lopes Sant’Ana, José Roberto R. Bortoleto, Nilson C da Cruz, Elidiane C Rangel, Steven F. Durrant, Laura Moreira Costa Botti, Carlos Alberto Rodrigues Anjos, Sofia Azevedo, Carine Isabel, Vasco Teixeira, Eber Antonio Alves Medeiros, Nilda de Fátima F Soares

International Journal of Nano Research, Vol. 1 (2018)

Available at: https://innovationinfo.org/articles/IJNR/IJNR-1-106.pdf

Best regards, Pierluigi Traverso

@ Pierluigi: I did not know these papers (I ought to!) and will go into them asap.Thank you very much!

@ Akanksha: My book recommendations are going back to earlier times, referring to the fundamentals of low-pressure plasmas.

J.R.Hollahan, A.T. Bell"Techniques and Applications of Plasma Chemistry", Ch.1,2,3,4: Fundamentals and mechanisms, Wiley, 1974,ISBN 0-471- 40628-7.

Brian Chapman"Glow Discharge Processes": Fundamentals of plasma physics and reactors, Ch. 1 to 4, Wiley, 1980, ISBN 0-471-07828-X.

Bernard D. Blaustein"Chemical Reactions in Electrical Discharges", Advan. Chem. Ser. 80, Ch. 3, and maybe, 9,18,24,25,

ACS 1969. Library of Congress Catalog Card 70-76951.

This is old stuff, but the basics did not change very much.

I learned from Pierluigi to invest more care into my answer.Thanks to him!

Best wishes

Heinrich

Pierluigi Traverso Thank you for the papers. Heinrich Gruenwald Even I did not know about these papers. I must upgrade the quality of my literature-search.

However, sources that both of you provided, have elucidated the concepts to me. Thank you again.