Irreversible bonding research of pdms membrane with cr39 optical resin

In order to improve the irreversible bonding characteristics of PDMS membrane with CR39 optical resin, and further expand the application space in microfluidic field of the optical material, the principle and process of various surface modification methods such as surface oxidation and chemical grafting are studied. The changes of IR spectra and surface contact angle α, which also present the change of the surface wetting property of PDMS membrane and CR39 optical resin, are tested by experiments. The experimental platform for bonding strength test is built, the bonding strength of the microfluidic optical chip samples under different test conditions is tested. The experimental results show that, after surface oxidation and chemical graft modification, the contact angles α of PDMS membrane and CR39 optical resin decrease obviously. The contact angles α of the two surfaces can be respectively stabilized at about 50° and 60° for a long time after the oxygen plasma & HEMA chemical graft combined modification. After the oxygen plasma & APTES combined modification, a dense Si—O—Si polymerization layer is formed between the bonded surfaces, and the chip bonding strength is the highest, up to 975 kPa. Therefore, it can be found that, different surface modification treatments can reduce the contact angle α of the surfaces to be bonded and enhance the wettability to varying degrees, oxygen plasma & APTES chemical graft combined modification is adopted as the optimal irreversible bonding method, which can greatly increase the bonding strength between the two bonded surfaces and effectively improve the reliability of the microfluidic optical chips.