A novel sequential dual-curable thermosetting system with a custom-tailorable structure based on a click thiol–epoxy reaction and excess epoxy is presented.

An extensive characterization of a sequential dual-curing system based on off-stoichiometric "thiol-epoxy" mixtures was carried out using thiol compounds of different functionality. The intermediate and final materials obtained after each curing stages at different thiol-epoxy ratios were studied by means of thermomechanical and rheological experiments. The storage and loss modulus and the loss factor tan δ were monitored during the curing process to analyse gelation and network structure build-up. The critical ratio for gelation was determined making use of the ideal Flory-Stockmayer theory and compared with experimental results. Intermediate materials obtained in the vicinity of the theoretical critical ratio did not have the mechanical consistency expected for partially crosslinked materials, did not retain their shape and even experienced undesired flow upon heating to activate the second curing reaction. The rheological results showed that the critical ratio is higher than the predicted value and that a softening during the second curing stage affects the shape-retention at this ratio. From the thermomechanical results, a wide range of intermediate and final materials with different properties and applicability can be obtained by properly choosing the thiol-epoxy ratio: from liquid-like to highly deformable intermediate materials and from moderately crosslinked (deformable) to highly crosslinked (brittle) final materials.

In this work, light and temperature responsive, brush‐painted photonic coatings exhibiting three different colored and surface topographical states are reported. The different states arise from the use of cholesteric liquid‐crystalline micrometer‐sized polymer particles as shape‐memory photonic pigments that are dispersed in a shape‐memory binder. The first temporal state is induced by compressing the photonic particles at high temperature, resulting in blueshift of the structural color. The second temporal state is obtained by embossing a diffractive grating on the surface at an intermediate temperature leading to a relief topography and a rainbow optical effect. Both optical and surface topographical changes coexist and are stable at room temperature until they are reverted independently either by heating or locally by light illumination. Multicolored paints that reflect selectively left‐handed or right‐handed polarized light are developed to create arbitrary polarization‐dependent multicolor and topographical brush‐painted patterns. These temperature and light responsive triple shape‐memory photonic paints have potential applications as battery‐free optical sensors, responsive decoration, and smart adhesives.

This paper presents a new methodology to develop "thiol-epoxy" shape-memory polymers (SMPs) with enhanced mechanical properties in a simple and efficient manner via "click" chemistry by using thermal latent initiators. The shape-memory response (SMR), defined by the mechanical capabilities of the SMP (high ultimate strength and strain), the shape-fixation and the recovery of the original shape (shape-recovery), was analyzed on thiol-epoxy systems by varying the network structure and programming temperature. The glass transition temperature (T g ) and crosslinking density were modified using 3-or 4-functional thiol curing agents and different amounts of a rigid triglycidyl isocyanurate compound. The relationship between the thermo-mechanical properties, network structure and the SMR was evidenced by means of qualitative and quantitative analysis. The influence of the programming temperature (T prog ) on the SMR was also analyzed in detail. The results demonstrate the possibility of tailoring SMPs with enhanced mechanical capabilities and excellent SMR, and intend to provide a better insight into the relationship between the network structure properties, programming temperature and the SMR of unconstrained (stress-free) systems; thus, making it easier to decide between different SMP and to define the operative parameters in the useful life.