Dear Sir. Concerning your issue about the chemical modification through introduction of hydrophilic functional groups on the surface of PS . Plastics that have a hydrophobic surface are generally given printable or adhesive properties through the modification of their surfaces to be hydrophilic. The modification process of plastic samples can be done by using microwave plasma irradiation to achieve a long-lasting hydrophilic surface. It was established that the two-step plasma processing technology gave plastic surfaces hydrophilicity lasting at least 80 days and more. Hydrophilic functional groups include hydroxyl groups (resulting in alcohols though also found in sugars, etc.), carbonyl groups (giving rise to aldehydes and ketones), carboxyl groups (resulting in carboxylic acids), amino groups(i.e., as found in amino acids), sulfhydryl groups (giving rise to thiols, i.e., as found in the amino acid cysteine), phosphate groups (as found in nucleic acids and phospholipids), etc. In addition are various hydrophilic linkages such as ethers (i.e., C-O-C), esters linkages (as found holding together fats, i.e., triglycerides), phosphodiester linkages (nucleic acids), glycolytic linkages (disaccharides and polysaccharides), and peptide bonds(polypeptides/proteins). I think the following protocols in the below links may help you in your analysis:

https://www.ihi.co.jp/var/ezwebin_site/storage/original/application/c73877fc235ab48d94af7b4563915734.pdf

http://doc.utwente.nl/71214/1/Terlingen95intro.pdf

http://www.biologyaspoetry.com/terms/hydrophilic_functional_groups.html

Thanks

 Thank you very much 

 Thank you Dr.ISAM 

• My question is the treatment by corona discharge is speedily,but cannot keep the hydrophilic properties of the polymer surface for long time.