The present invention provides modified multifunctional thiol-ene monomers wherein one or more thiols are reacted with a Michael addition reactive double bond compound. The present invention further discloses photocurable thiol-ene formulations comprising thiol-ene monomers including the modified multifunctional thiols. The present invention further discloses photocurable thiol-ene formulations comprising thiol-ene monomers and Michael addition reactive double bond molecules and a Michael catalyst. The formulations of the present invention can be photocured to make films or coatings. In a further disclosure, the formulations, including those comprised of unmodified multifunctional thiols and multifunctional enes, are photocured to form films applied to non-flexible or flexible polymer or non-polymer substrates suitable for food packaging, electronic products, optical products and other applications and free-standing films. The present invention further discloses photocurable thiol-ene formulations comprising thiol-ene monomers and Michael addition reactive double bond molecules and a Michael catalyst. These formulations are disclosed to form free-standing films and coatings on substrates when applied to flexible substrates. Such materials are suitable for use in the packaging of food products and other products which are to be maintained in a hermetically sealed relationship to the atmosphere.