TY - JOUR

T1 - Wavelength-Dependent Dynamic Behavior in Thiol-Ene Networks Based on Disulfide Exchange

AU - Sölle, Bernhard

AU - Schmallegger, Max

AU - Schlögl, Sandra

AU - Rossegger, Elisabeth

N1 - Publisher Copyright: © 2024 The Authors. Published by American Chemical Society.

PY - 2024/12/1

Y1 - 2024/12/1

N2 - While latent catalysts have become a well-established strategy for locally and temporally controlling bond exchange reactions in dynamic polymer networks, there is a lack of inherently tailorable systems. Herein, we introduce a thiol-ene network based on disulfide exchange that alters its dynamic properties as a function of the color of light used during the curing reaction. For this purpose, selected allyl-bearing disulfides are synthesized, which are transparent at 450 nm but undergo disulfide scission upon 365 nm light irradiation, as confirmed by UV-vis and EPR measurements. Incorporated into a thiol-ene resin, the wavelength used in the curing reaction defines the dynamic properties of the obtained photopolymer. At 450 nm, photocuring yields a dynamic network with disulfide bonds, which relaxes to 63% of its original stress within 112 s at 160 °C (without the requirement of an external catalyst). In contrast, curing with 365 nm light induces disulfide scission yielding photopolymers, which contain predominately monosulfidic links. The permanent nature of the links effectively prevents relaxation of the polymer within a reasonable period of time, confirming the successful alteration of its dynamic properties simply by the color of the light source used.

AB - While latent catalysts have become a well-established strategy for locally and temporally controlling bond exchange reactions in dynamic polymer networks, there is a lack of inherently tailorable systems. Herein, we introduce a thiol-ene network based on disulfide exchange that alters its dynamic properties as a function of the color of light used during the curing reaction. For this purpose, selected allyl-bearing disulfides are synthesized, which are transparent at 450 nm but undergo disulfide scission upon 365 nm light irradiation, as confirmed by UV-vis and EPR measurements. Incorporated into a thiol-ene resin, the wavelength used in the curing reaction defines the dynamic properties of the obtained photopolymer. At 450 nm, photocuring yields a dynamic network with disulfide bonds, which relaxes to 63% of its original stress within 112 s at 160 °C (without the requirement of an external catalyst). In contrast, curing with 365 nm light induces disulfide scission yielding photopolymers, which contain predominately monosulfidic links. The permanent nature of the links effectively prevents relaxation of the polymer within a reasonable period of time, confirming the successful alteration of its dynamic properties simply by the color of the light source used.

UR - http://www.scopus.com/inward/record.url?scp=85210945258&partnerID=8YFLogxK

U2 - 10.1021/jacs.4c13735

DO - 10.1021/jacs.4c13735

M3 - Article

C2 - 39616608

AN - SCOPUS:85210945258

VL - 146.2024

SP - 34152

EP - 34157

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 49

ER -