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The 4D additive manufacturing processes are considered today as the "next big thing" in R&D. The aim of this research is to provide two examples of commercial PLA based shape memory polymer (SMP) objects printed on an open-source 3D printer in order to proof the feasibility of such novel 4D printing process. To that purpose, a PLA based filament of eSUN (4D filament e4D-1white, SMP) was chosen, and two applications, a spring and a vase, were designed by 3D-printing with additive manufacturing (AM) fused filament fabrication (FFF) technique. The 4D-printed objects were successfully produced, the shape memory effect and their functionality were demonstrated by achieving the shape-memory cycle of programming, storage and recovery.

In the past few years four-dimensional (4D) printing technologies have attained worldwide interest and they are now considered the "next big thing". The aim of this research is to provide three selected examples of stimuli-responsive polymer (SRP) applications additively manufactured (AM) by the fused filament fabrication (FFF) technique. To that end, a CCT BLUE filament of thermo-responsive polymer was chosen to produce a water temperature indicator, which changes colour from blue to white when temperature increases; a CCU RED filament of photo-responsive polymer was used to produce a sunlight / UV indicator bracelet; a transparent PLA CLEAR polymer, a CCU RED photo-responsive polymer, and an electrical conductive PLA polymer were selected to produce a smart business card stand. The temperature indicator capability was analysed based on examining colour changes as a function of temperature changes. The sunlight/UV indicator capability was analysed based on the inspection of colour change as a function of absorbed sun/ultraviolet light. The electrical conductivity of the conductive PLA polymer was examined by performing resistance measurements. All three objects were successfully produced and their functionality was demonstrated. We hope that these examples will catalyse the expansion of FFF 4D printed SRP applications, as much work remains to be done in designing the parts and developing FFF printing parameters that take advantage of the stimuli-responsive materials currently being developed for FFF technology.