Initiator-free photo-cross-linkable cellulose-based resists for fabricating submicron patterns via direct laser writing

Novel bifunctional cellulose diacetate derivatives were synthesized in order to achieve bio-based photoresists, which can be structured by two-photon absorption via direct laser writing (DLW) without the need to use a photoinitiator. Therefore, cellulose diacetate is functionalized with thiol moieties and olefinic or methacrylic side groups enabling thiol-conjugated cross-linking. These cellulose derivatives are also photo-cross-linkable via UV irradiation (𝜆=254nm and 365 nm) without using an initiator.