Functional materials for Design

The main problematic of the research is to connect the stimuli-responsive behaviour of functional material to the end-user experience. To make this connection, the research was divided in layers, from the most technical at the bottom, to the most designerly at the top. The objective is to propose a set of chained tools that will eventually allow a seamless journey through all the layers and provide support for designers to use functional material in their projects

Tunable architecture for flexible and highly conductive graphene-polymer composites

International audiencePrinted electronics, particularly on flexible and textile substrates, raised a strong interest during the past decades. This work presents a good candidate for conductive inks based on a graphene/polymer nanocomposite material that gathers three main benefits that are 1 - neither clogging nor flocculation, 2 - spontaneous film formation around room temperature, 3 - high conductivity. Nanosized Multilayered Graphene (NMG) is produced through a solvent-free procedure, using a grinding process in water. These NMG suspensions are used to elaborate conductive composite materials through physical blending with emulsifier-free latex. The nanocomposite microstructure exhibits a well-defined cellular architecture that highlights the formation of continuous paths of fillers throughout the material. The conductivity behavior of the nanocomposite material was efficiently described using a percolation model: the conductivity can be tuned by changing the NMG content and the latex size. A low percolation threshold (0.1 vol%) was obtained and the electrical conductivity reached 217 S m−1 for 6 vol% NMG. Efficient film forming occurs at room temperature leading to continuous and deformable materials, which is adequate for printing on flexible and textile substrates. The applicability in electronics is demonstrated by the use of the nanocomposite material in replacement of copper wires in a LED setup

Selection Framework for the Implementation of Functional Materials in Product Design

Concept Functional materials, also called “smart materials”, are materials that can “sense environment events, process that sensory information and then act on the environment” [1]. These materials are able to transform a given stimulus into a response. We use the general term “transition phenomenon” to describe this process. These transitions can be as diverse as, e.g.: mechanoluminescence, which is a light emission produced by the application of a strain [2], or thermoelectricity, the convertion of a temperature difference into an electric potential [3]. We designed a specific database and selection process for functional materials. The data structure is organized around their main functionality: the transition phenomenon. This database is implemented in the Cambridge Engineering Selector software, using the “constructor” functionality. Motivations and Objectives The standard selection framework proposed by Ashby [4] relies on 4 successive stages : translation, limits, objectives, documentation. It is not entirely suited to the selection of functional materials, which has to account for the relation between stimuli and responses. Results and Discussion In our database prototype, we introduce a table of transition phenomena, which is organized by families and sub-families of outputs (Fig 1). The relationship between materials and transition phenomena is made by linking the tables together and providing specific attributes that describe the stimuli-responsive properties of the materials. Future developments include tables of existing products and processes used to implement functional materials or functionalize existing ones. In this work, as the entry point to the information system is the stimuli responsive behaviour of functional materials, rather than their structure and properties. The emphasis is thus put on user experience and interaction with materials and products. References [1] M. Addington, D. Schodek, Smart Materials and technologies for the architecture and design professions, Elsevier, 2005 [2] S. M. Jeong, S. Song, K.-I. Joo, J. Kim, S.-H. Hwang, J. Jeong, H. Kim, Bright, wind-driven white mechanoluminescence from zinc sulphide microparticles embedded in a polydimethylsiloxane elastomer [3] A. da Rosa, Thermoelectricity, Fundamentals of Renewable Energy Processes, Elsevier, 2013, 149–212 [4] M. Ashby, Materials Selection in Mechanical Design, Elsevier, 1992-2005(Third edition

Mapping circular economy projects: a case study of a major company in the sports & outdoor industry

Abstractparticipants have an average annual carbon footprint of 844 kg of carbon dioxide-equivalent emissions. Thus, it is crucial to find solutions that reduce the sports industry's environmental impact. In this context, the circular economy emerges as a possible alternative. This paper analyses a sports production and retail company transitioning to the circular economy. First, we identified 154 internal circular projects concerning 89 product categories and classified them into different circular strategies and approaches. Then, we conducted interviews with 33 project representatives. Our results show that repair & maintenance is the most employed loop, but sharing economy and recycling also have an essential role. Each circularity loop presents specific challenges, but personal conviction is the common motivator. However, there is a need for greater allocation of resources such as time and budget. Additionally, strong governance is essential to structure these initiatives

Stimuli-responsive materials: Definition, classification and descriptions

Stimuli-responsive materials: definition, classification and descriptions Stimuli-responsive materials have the particularity to change one or more of their properties under a defined stimulus: through a transition phenomenon, they will turn an input, or stimulus, into an output, or response. To make a selection of these materials, a designer will consider first of all the main functionality of these materials, which is their transition phenomenon, as it gives them a capacity to process information. To get a perspective on stimuli-responsive materials and the possibilities they offer, the first step has been to class them according to their transition phenomenon. This has been done in the form of a graph where transition phenomena are represented as a link between their associated input and output. A second representation has been made starting from the first graph, but adding a link to the user of a product which use a stimuli-responsive material. To do so, the inputs of the materials has been differentiated by the fact that they can be activated by the user, the environment or by an intermediary system; the outputs has been linked to the achievable behaviors of a product and with the sensory modality the user will engage to notice these behaviors. After having proposed this classification of stimuli-responsive materials, the next step of the work is to get more detailed information about their behavior, and to organize and represent this information in a coherent and efficient way. To do so, we proposed a description for each type of transition phenomenon, which shows its most important characteristics in a visual way. This information is now being summed up in a database, which is organized with different tables and tree-structures that will describe stimuli-responsive materials, transition phenomena and the link between them. A first prototype of the database will be proposed

Relations microstructures-propriétés dans des films nanostructurés élaborés par voie latex

La philosophie de ce projet est d\u27utiliser les particules de latex en tant que brique élémentaire nanostructurée pour construire le matériau final nanostructuré à son tour. Un latex est une suspension colloïdale de particules de polymère dans l\u27eau stabilisée par la présence de molécules de tensioactifs. Un film continu est obtenu après évaporation d\u27eau et coalescence des particules. Deux types de " charges " ont été considérés : une charge minérale (argile nanométrique) et une charge polymerère (résine alkyde susceptible de réticuler). Le succès de l\u27introduction a l\u27échelle nanométrique de ces secondes phases repose sur une polymérisation in-situ (miniémulsion) en présence de cette seconde phase. Il a été montré que dans les deux stratégies, la nanostructuration du matériau a une influence sur la distribution du surfactant et de ce fait sur les propriétés de prise en eau. De plus la présence d\u27un réseau percolant de nanocharges entraîne une augmentation brutale du renforcement

Heuristic Evaluation of Ambient Devices Using Smart Materials

International audienceTeaching “calm technology” and “smart materials” as prospective trends in product design is the motivation of the educational workshop presented in this paper. Materials can trigger creative thinking. Indeed, concepts can be generated ideas that come from the encounter with a material showing the material's unexpressed potential. However, a smart material is a complex hybrid object. It is a highly technical matter that requires years of R&D to be developed and matured. It is also a highly social matter, that blurs the traditional boundary between matter and function in a product, creates an experience, and enhances sensations. The workshop presented in this paper is an opportunity for the students to analyze the complexity of user experience related to ambient devices using smart materials. In order to provide a guideline to perform this analysis, an approach based on heuristic evaluation is proposed to the students

VO₂-polymer nanostructured coatings for smart windows: a numerical study

International audienceThermochromic vanadium dioxide loaded into a polymer opal photonic crystal is studied through optical simulations. The possibility of using this material as flexible transparent energy efficient smart material is explored

Numerical study of the thermally adaptive emissivity of VO2-polymer nanostructured coatings

The emissivity of an opal photonic crystal loaded with thermochromic VO2 nanoparticles is studied through optical calculations, highlighting the influence of the structure by comparison with a homogenized model. Parameters are first set to maximize the structure influence on material emissivity. Then, a full study of the influence of the VO2 concentration is made to identify, on one hand, cases with the highest structure impact, and on the other hand, interesting cases for applications such as energy-efficient coatings for buildings, satellites, and camouflage applications