US 12,429,766 B2
Photoresist formulations 3D microprinting techniques
Marco Carlotti, Pisa (IT); Omar Tricinci, Pietracamela (IT); and Virgilio Mattoli, Pisa (IT)
Assigned to FONDAZIONE ISTITUTO ITALIANO DI TECNOLOGIA, Genoa (IT)
Appl. No. 18/562,549
Filed by FONDAZIONE ISTITUTO ITALIANO DI TECNOLOGIA, Genoa (IT)
PCT Filed May 20, 2022, PCT No. PCT/IB2022/054718
§ 371(c)(1), (2) Date Nov. 20, 2023,
PCT Pub. No. WO2022/249002, PCT Pub. Date Dec. 1, 2022.
Claims priority of application No. 102021000013421 (IT), filed on May 24, 2021.
Prior Publication US 2024/0201585 A1, Jun. 20, 2024
Int. Cl. G03F 7/00 (2006.01); B33Y 10/00 (2015.01); B33Y 70/00 (2020.01); B33Y 80/00 (2015.01); G03F 7/031 (2006.01)
CPC G03F 7/0037 (2013.01) [B33Y 10/00 (2014.12); B33Y 70/00 (2014.12); B33Y 80/00 (2014.12); G03F 7/031 (2013.01); G03F 7/70025 (2013.01); G03F 7/70375 (2013.01)] 19 Claims
OG exemplary drawing
 
1. 3D micro-printing process via two-photon polymerisation for producing degradable 3D polymeric nano- or microstructures having sub-micrometre resolution, said process comprising the steps of:
(a) providing a photoresist formulation comprising:
(i) Cyclic ketene acetal monomers of general formula (I):

OG Complex Work Unit Chemistry
selected from the group consisting of:
2-methylene-1,3-dioxane, 4-methyl-2-methylene-1,3-dioxane, 4,4,5,5-tetramethyl-2-methylene-1,3-dioxane, 2,4-dimethylene-1,3-dioxane, 2-methylene-hexhydrobenzo[d][1,3]dioxole, 2-methylene-1,3-dioxane, 4,6-dimethyl-2-methylene-1,3-dioxane, 5,5-dimethyl-2-methylene-1,3-dioxane, 2-methylene-4-phenyl-1,3-dioxane, 2-methylene-5,5-diphenyl-1,3-dioxane, 2-methylene-1,3-dioxepane (MDO), 4,7-dimethyl-2-methylene-1,3-dioxepane, 3-methylene-1,5-dihydrobenzo[e][1,3]dioxepine, 4-methylene-3,5-dioxabicyclo[5.1.0]octane, 2-(difluoromethylene)-1,3-dioxepane, 5,6-dimethoxy-2-methylene-1,3-dioxepane, 2-methylene-1,3-dithiepane, 3,9-dimethylene-1,5,8,10-tetraoxaspiro[5.5]undecane, and a combination thereof;
(ii) vinyl and/or (meth)acrylic monomers selected from the group consisting of: pentaerythritol tetraacrylate, pentaerythritol triacrylate, 1,4-butanediol diacrylate, 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, bisphenol A diacrylate, tricyclo[5.2.1.02,6]decanedimethanol diacrylate, trimethylolpropane triacrylate, ethyl acrylate, ethylene-methyl acrylate, methyl methacrylate, 2-chloroethyl vinyl ether, 2-hydroxyethyl acrylate, hydroxyethyl methacrylate, butyl acrylate, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, chloroprene, styrene, and a combination thereof;
(iii) at least one photoinitiator;
(b) focusing a laser beam within said photoresist formulation by directing said laser beam until localised polymerisation of said photoresist into a 3D cross-linked polymeric nano- or microstructure is achieved;
(c) removing the non-cross-linked portion of photoresist by washing with a solvent.