Photoinduced Cross-Linking of Dynamic Poly(disulfide) Films via Thiol Oxidative Coupling.
Initially developed as an elastomer with an excellent record of barrier and chemical resistance properties, poly(disulfide) has experienced a revival linked to the dynamic nature of the S-S covalent bond. A novel photobase-catalyzed oxidative polymerization of multifunctional thiols to poly(disulfide) network is reported. Based solely on air oxidation, the single-step process is triggered by the photodecarboxylation of a xanthone acetic acid liberating a strong bicyclic guanidine base. Starting with a 1 μm thick film based on trithiol poly(ethylene oxide) oligomer, the UV-mediated oxidation of thiols to disulfides occurs in a matter of minutes both selectively, i.e., without overoxidation, and quantitatively as assessed by a range of spectroscopic techniques. Thiolate formation and film thickness determine the reaction rates and yield. Spatial control of the photopolymerization serves to generate robust micropatterns, while the reductive cleavage of S-S bridges allows the recycling of 40% of the initial thiol groups.
Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Noémi
N
Feillée
Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Abraham
A
Chemtob
Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Christian
C
Ley
Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Céline
C
Croutxé-Barghorn
Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Xavier
X
Allonas
Institute of Mulhouse Material Science, UMR-CNRS 7361, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Arnaud
A
Ponche
Laboratory of Organic and Bioorganic Chemistry, University of Haute-Alsace, 3 rue Alfred Werner, 68093, Mulhouse Cedex, France.
Didier
D
Le Nouen
Institut de Physique et Chimie des Matériaux de Strasbourg, UMR-CNRS 7504, University of Strasbourg, 23 rue du Loess, BP 43, F-67034, Strasbourg Cedex 2, France.
Hicham
H
Majjad
Institut Charles Sadron, University of Strasbourg, CNRS-UPR22, University of Strasbourg, 23 rue du Loess, BP, 84047, F-67034, Strasbourg Cedex 2, France.
Léandro
L
Jacomine
D002384:Catalysis; D004220:Disulfides / Q000737:chemistry*; D006146:Guanidines / Q000737:chemistry*; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D058451:Oxidative Coupling; D055668:Photochemical Processes; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D044004:Xanthones / Q000737:chemistry*
D004220:Disulfides; D006146:Guanidines; D013438:Sulfhydryl Compounds; D044004:Xanthones; D011092:Polyethylene Glycols
cross-linking; photopolymerization; photoresists; polysulfides; recycling