Addition of Photosensitivity to Hyperbranched Engineering Plastics based on Reaction Development Patterning

We investigated mechanism of the dissolution of HBPE-NO2 films to the developer by analysis of the developer after development. A HBPE-NO2 film containing BADNQ2 was irradiated with 500 mJ/cm2 of exposure dose and developed with 25wt% TMAHaq. The developer was then neutralized by HClaq. and the solution was evaporated and dried at 90 °C in vacuo. 1H-NMR spectrum of the resulting product after development is shown in Fig. 3. The 1H-NMR spectrum shows signals assigned to the monomers, terephthalic acid derived from TPC and THPE, and 4-nitrobenzoic acid derived from the end groups. However, no signal that can be assigned to the original HBPE-NO2 protons was observed. This result suggests that RDP of HBPE-NO2 is not based on solubilization of the polymer by the reaction at the end groups but on decomposition of the polymer induced by nucleophilic attack of the OH- to the ester linkages to give low-molecular-weight products.