Acid‐Catalyzed degradation mechanism of poly(phthalaldehyde): Unzipping reaction of chemical amplification resist

Chemically amplified resists. VII. proton generation from triphenyl sulfonium salts via photochemical isomerization mechanism.

“…From those calculations carried out in this paper, we conclude that the concerted mechanisms are mainly operated in the direct photolysis of triphenylsulfonium salts in the singlet states, whereas the homolytic bond-dissociation mechanism is operated in the triplet state arisen from photo-irradiation as well as in the triplet-sensitized photolysis as shown in the previous paper [4] . This mechanism presented here explains clearly the two serious questions indicated above.…”

Photodegradable transient bilayered poly(phthalaldehyde) with improved shelf life

“…The rate‐limiting step is PPHA depolymerization after the initial chain scission ring‐opening reaction . Chain scission ring opens the cyclic polymer and activates (deprotects) the newly created chain ends, initiating the rapid depolymerization of PPHA back to monomer .…”

Sunlight photodepolymerization of transient polymers

“…Films were exposed to midday sunlight, 1034 W m −2 . PPHA can depolymerize by protonation of the PPHA ether linkage creating cationic hydroxyl groups that lead to an unzipping decomposition reaction producing phthalaldehyde . Acid‐catalyzed depolymerization of PPHA can occur at temperatures above its ceiling temperature (−43 °C), which makes it suitable for transience applications at ambient conditions.…”