Multimaterial 4D Printing with Tailorable Shape Memory Polymers

We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures

Morphing in nature and beyond: a review of natural and synthetic shape-changing materials and mechanisms

Shape-changing materials open an entirely new solution space for a wide range of disciplines: from architecture that responds to the environment and medical devices that unpack inside the body, to passive sensors and novel robotic actuators. While synthetic shape-changing materials are still in their infancy, studies of biological morphing materials have revealed key paradigms and features which underlie efficient natural shape-change. Here, we review some of these insights and how they have been, or may be, translated to artificial solutions. We focus on soft matter due to its prevalence in nature, compatibility with users and potential for novel design. Initially, we review examples of natural shape-changing materials—skeletal muscle, tendons and plant tissues—and compare with synthetic examples with similar methods of operation. Stimuli to motion are outlined in general principle, with examples of their use and potential in manufactured systems. Anisotropy is identified as a crucial element in directing shape-change to fulfil designed tasks, and some manufacturing routes to its achievement are highlighted. We conclude with potential directions for future work, including the simultaneous development of materials and manufacturing techniques and the hierarchical combination of effects at multiple length scales.</p

Ultra personalization and textile thinking in interaction design

\u3cp\u3eTextile Thinking and Ultra Personalization are guiding the PhD research in wearable on body sensing in the creation of garments / accessories. Textile Thinking involves the superficial surface of a design process that attempts to create a point of view to reach new understandings in design and architecture. When applied to interaction design in the near field the garments that people wear can become an interface or expression for sensing and actuating. Specific ideas such as Fit are explored to aid in developing a more unique understanding of interaction on the body.\u3c/p\u3

Mechanics of biomimetic 4D printed structures

© 2018 The Royal Society of Chemistry. Recent progress in additive manufacturing and materials engineering has led to a surge of interest in shape-changing plate and shell-like structures. Such structures are typically printed in a planar configuration and, when exposed to an ambient stimulus such as heat or humidity, swell into a desired three-dimensional geometry. Viewed through the lens of differential geometry and elasticity, the application of the physical stimulus can be understood as a local change in the metric of a two dimensional surface embedded in three dimensions. To relieve the resulting elastic frustration, the structure will generally bend and buckle out-of-plane. Here, we propose a numerical approach to convert the discrete geometry of filament bilayers, associated with print paths of inks with given material properties, into continuous plates with inhomogeneous growth patterns and thicknesses. When subject to prescribed growth anisotropies, we can then follow the evolution of the shapes into their final form. We show that our results provide a good correspondence between experiments and simulations, and lead to a framework for the prediction and design of shape-changing structures

3D Bioprinting of Vascularized, Heterogeneous Cell-Laden Tissue Constructs

A new bioprinting method is reported for fabricating 3D tissue constructs replete with vasculature, multiple types of cells, and extracellular matrix. These intricate, heterogeneous structures are created by precisely co-printing multiple materials, known as bioinks, in three dimensions. These 3D micro-engineered environments open new ­avenues for drug screening and fundamental studies of wound healing, angiogenesis, and stem-cell niches.Engineering and Applied Science

Material Agency and 4D Printing

Material agency presents a radical shift in design thinking: matter is deemed as the active generator of design. This chapter investigates the potentialities of the synergy between adaptive materials and emergent additive manufacturing techniques. In this context, 4D printing is explored as the tool that enables the material-centered design and fabrication approach. By means of this technique, it is possible to generate stimuli-responsive material systems that can enact self-adaptation of architectural constructs, responding to environmental change with a shape-shifting behaviour. Moreover, a fast, innovative, 3D printing method, Rapid Liquid Printing, allows for this process to potentially scale up to an architectural scale, as it offers the opportunity of quickly printing at large-scales with a wide array of materials, from industrial grade rubbers to responsive silicones