Dispersion of Gold Nanoparticles in UV-Cured, Thiol−Ene Films by Precomplexation of Gold−Thiol

Abstract

Alkyl thiols and alkenes (enes) polymerize via an extremely rapid step-growth, free-radical chain process, uninhibited by air, to give high-density networks with excellent mechanical and physical properties. These thiol-ene coatings are potentially useful for a wide variety of coatings, adhesives, and optical applications. In this work, a series of nanogold-containing UV-cured, thiol-ene coatings were prepared from trimethylolpropane tris(3-mercaptopropionate) (trithiol) and pentaerythritol allyl ether (triene) monomers using a unique procedure which facilitates precomplexation of the gold-thiol prior to photocuring. Irgacure 651 (1 wt %) was used as a photoinitiator, and nanogold was incorporated at 0-1 wt %, average ∼10 nm size particles by TEM. Physical and mechanical properties were characterized using bulk tack analysis and other standard techniques: DSC, TGA, pencil hardness, and gel fractions. In general, films were found to be low absorbing in the visible range and highly uniform and to contain well-dispersed nanogold particles. Although the rate of polymerization was modestly retarded by the presence of gold nanoparticles, functional group conversions (CdC and S-H) and gel fractions were high. Increasing nanogold content resulted in an increase in T g measured by DSC (-15 to -8 °C for 0-1 wt % nanogold, respectively) due to the increasing number of physical gold-thiol cross-links created. TGA analysis revealed a small negative impact of increasing nanogold composition on relative thermal stability. The 1 wt % nanogold-containing samples possessed appreciable electrostatic discharge (ESD) character, with ESD times of 1-10 s measured using a commercial charge plate analyzer.

Facile Fabrication of Color Tunable Film and Fiber Nanocomposites via Thiol Click Chemistry

“…Only after the AuNS were visibly well dispersed in the thiol material was the alkene added, thus completing the AuNS thiol−ene prepolymer preparation. 14 In the method used in this report, AuNS were functionalized with ligands prior to their complexation into the thiol−yne or thiol−ene prepolymers. Because the thiol−yne and thiol−ene prepolymers were largely composed of hydrophobic components, it is plausible that the surface functionalization of the AuNS with a monolayer of hydrophobic ligand made them more compatible with the prepolymers.…”

Sulfur and Its Role In Modern Materials Science

“…[57] Mechanical analysis of the thiol-ene nanocomposites indicated an increase in the glass transition temperature,b ut ad ecrease in the degradation onset temperature as the AuNP concentration increased. [57] Mechanical analysis of the thiol-ene nanocomposites indicated an increase in the glass transition temperature,b ut ad ecrease in the degradation onset temperature as the AuNP concentration increased.…”

Macroscopic Self‐Assembly and Optical Characterization of Nanoparticle–Ligand Metamaterials

“…Once the reaction is complete the thiol-ene capped nanospheres are exposed to UV-light for several seconds to initiate ligand crosslinking, via thiol-ene click chemistry [ 17 ] to create a crosslinked fi lm of nanoparticles. After shaking, the nanoparticle fi lms translate up the substrate in the same manner as the sides of the glass vial.…”