With the growing popularity of virtual and augmented reality, there is an increasing demand for haptic devices that can replicate naturally occurring tactile sensations. Specifically, multimodal devices capable of delivering multiple types of haptic feedback simultaneously are crucial for enhancing realism and immersion. In this paper, we introduce a novel, entirely soft, multimodal haptic ring designed to provide vibratory, pressure, and thermal stimuli. Our ring, targeted for texture rendering applications, integrates pneumatic and hydraulic circuits to accurately simulate the roughness, temperature, and compliance cues experienced when freely exploring surfaces with the fingertip. We validated the performance of our system through a psychophysical experiment, which demonstrated that participants could match virtual textures displayed by the ring with real textures with up to 90 % accuracy for several surfaces. Participant’s adjectives ratings indicated that the ring can provide distinctly different stimuli in all of the rendered perceptual dimensions, closely matching those of real textures. This study shows that by relocating tactile feedback from the fingertip, our ring offers maximum wearability, enabling free exploration of surrounding environments and full range of motion, highlighting its potential in mixed reality applications.

This project addresses the gap in current stress-regulation treatments by developing a smart textile wearable that integrates shape-morphing materials and body monitoring sensors to regulate the nervous system through conscious breathing. Anxiety, recognized as the leading chronic stress-related disorder globally by the World Health Organization, often remains inadequately treated due to the lack of advanced mental health solutions which fail to integrate into daily life, resulting in underutilization and insufficient awareness. Consequently, existing solutions are either focused solely on body monitoring or haptic feedback, typically involving bulky and noisy electromechanical systems. This project aims to bridge this gap by combining both elements into a discreet, non-intrusive abdominal wearable, designed for everyday use to enhance individual awareness of anxious conditions and facilitate self-management.

By utilizing Shape Memory Alloys (SMAs) for their advantageous power-to-weight ratio and ease of integration into textiles, this project explores their potential to simulate diaphragmatic breathing rhythms, aiding users in managing anxiety. Guided by the Material Driven Design (MDD) methodology, the project synthesizes theoretical and empirical research to develop a wearable prototype that accurately replicates breathing rhythms through SMA, monitors heart rate, and ensures user comfort and a soothing experience. Experimental studies with 0.5mm NiTiCu SMAs in zigzag configurations demonstrate the feasibility of reducing response time and controlling expansion movements at a high deformation strain, enhancing the simulation of breathing rhythms. A new SMA re-training method was identified, which conserves time, effort, and energy without necessitating high temperatures above 500ºC.

User studies indicate a strong preference for active engagement in haptic breathing guidance, which enhances focus and personal connection to the device. The wearable’s slow, organic expansion-contraction movements on the abdomen closely mimic natural diaphragmatic breathing, facilitating synchronization and promoting a sense of calm. The prototype’s dual association with medical and personal contexts, combined with its portability, supports versatile use across different settings and postures, thereby contributing to a positive user experience. The findings demonstrate the device’s efficacy in heightening user awareness and managing high stress, presenting a promising solution for health applications. This project provides significant insights into the integration of SMAs and smart textiles for mental health applications, presenting a noiseless, lightweight, discreet, and non-invasive solution.

In medical applications such as medical endovascular catheters, adaptable and morphing devices capable of changing shape and properties become important. These devices allow for safer therapeutic and diagnostic procedures by reducing time to reach target vessels and organs, trauma to the vessel wall and physical stress on the body while increasing the accuracy, benefits and positive outcomes. A catheter with these properties will also reduce X-ray exposure during procedures, recovery time and could save lives in the acute setting.

In the field of emerging materials, several materials demonstrate variable properties when exposed to a stimulus. This, when combined with the field of minimally invasive surgery, holds significant potential for the development of a catheter with variable shape and properties.

This thesis investigates the latest developments in endovascular catheter design through a materials lense. It begins with a thorough examination of material-based advancements in catheters with variable properties, and puts a particular focus on shape memory materials. Using a combination of literature review, field work examination and expert consultations, the design of a catheter with variable properties is comprehensively analyzed and evaluated.
Prototyping was done to evaluate the potential of two material systems to achieve variable behaviour in the design of a catheter.

The study presents a conceptual shape memory material-based design for a catheter with variable shape and properties and demonstrates this with a visual prototype. Additionally, potential directions for further refinement of this conceptual design are explored. This thesis serves as an initial reference and guiding framework for designers working with emerging materials in the field of medical devices and in particular the development of endovascular catheters with variable properties.

People who suffer from tremor, experience uncontrollable, involuntary movements. Depending on the underlaying cause, these movements occur during rest, or simultaneous with voluntary movements.
STIL is a YES!Delft based, med-tech startup that is developing a non-invasive, anti-tremor orthosis that helps people with tremors in their upper limbs. The current anti-tremor orthosis helps with the reduction of upper limb tremor. However, it limits the mobility of the user’s hand and wrist. Motion in the Wrist Radial and Ulnar Deviation (WRUD) degree of freedom are limited due to the way the orthosis is designed.

By redesigning several parts of the orthosis, a new degree of freedom has been added to the device.
This increased mobility makes the orthosis more comfortable in daily use, and could even be beneficial to the suppression of upper limb tremor.

By integrating a small mechanical damper, the friction in the WRUD degree of freedom can be controlled.
A system of interlocking parts, supported by dampers ensure a durable and smooth rotation when the wrist is moved.
The fully functional prototype was manufactured and handed over to STIL bv for further testing, along with recommendations to optimize the design .

Suction grippers have the advantage to handle many different types and sizes of items, without being restricted by the dimensions of clamps to enclose an object and to handle objects more delicately.
However, the challenge of attaching these grippers to irregularly-shaped and rough surfaces remains a persistent issue. Despite advancements in research, the possibilities for miniaturisation, specific control, speed, and universal gripping capabilities still pose significant challenges. This study aims to overcome these obstacles by embedding magnetic intelligence within the material of a suction gripper and enabling the actuation of the attachment by an external magnetic field.
In this study, magnetic responsive soft materials are explored and different suction mechanisms are designed and validated to explore the opportunities of a magnetically actuated suction gripper. The miniaturisation options of the gripper are improved by implementing a compliant deploying mechanism. This results in the design of a magnetic actuated deployable suction gripper, using a thin magnetic membrane consisting of carbonyl iron particles in a silicone matrix material, in a frame of superelastic nitinol providing pressure on the rim and allowing for deploying.
A proof-of-principle prototype has been experimentally validated for attachment performance on a variety of curved surfaces in both dry and wet environments.
The attachment was achieved on curved surfaces with a radius of 50mm and 75mm, with a maximum attachment force of 2.89 \textpm 0.54 N. Observation suggests that only on surfaces with a curvature that is positioned exactly at the rim of the gripper attachment is not possible. For these surfaces, the nitinol wire rim prevented the flexible footprint membrane to seal onto the surface and leakage occurred.
The current gripper design is able to achieve a 75\% folding percentage, which allows it to enter hard-to-reach places in a small configuration while remaining enough surface area for attachment forces.
The proposed prototype serves as a foundation for further research in the development of reliable and effective magnetic-actuated suction grippers in a variety of configurations.

With growing concern over our reliance on non-renewable resources and the environmental impact of conventional manufacturing, the quest for sustainable materials and production processes has intensified. This pursuit has extended to the field of additive manufacturing, where bio-materials have emerged as promising alternatives, aiming to reduce energy consumption and utilise material waste streams. While biopolymers like PLA are a good step forward, they still pose sustainability challenges, primarily related to energy-intensive melting processes, competition with food sources for production, slow biodegradability, and inadequate waste disposal systems. Consequently, researchers have turned to utilizing biomass waste streams to create 3D printable materials that solidify at ambient temperatures. However, the currently existing bio-based materials for ambient printing exhibit inconsistencies in quality. To allow for commercial adoption of these materials, enhancements in print quality are necessary.

This thesis addresses the core issue of lower print quality in room-temperature printing of biomaterials. Its primary aim is to develop and optimize the print quality of these materials, fostering a deeper understanding of the key factors that influence their printing performance. Within the context of print quality, the study examines parameters such as dimensional accuracy, bridging, overhang performance, warpage, corner sharpness, surface finish, and precision. Furthermore, the research investigated the feasibility of reprinting these materials and its impact on their print quality. Extra attention was dedicated to investigating the influence of the rheology characteristics of the materials on the resulting print quality.

The research led to the creation of two materials, AB1 and CLAB4 and the optimization of print parameters to enhance their print quality. In doing so it elaborates on the influences of material composition, preparation and printing parameters on the print quality of biomaterials printed at room temperatures.
Of the materials developed, AB1 demonstrated exceptional bridging capabilities, achieving distances of up to 15 mm, minimal shrinkage (averaging 6% in the xy-directions and 4% in the z-direction), and good result precision. In contrast, CLAB4 excelled in surface finish, printing overhangs up to 40 degrees, and showcased higher efficiency in material preparation. Most noteworthy of both materials is their reprintability without evident degradation in print quality, a crucial feature for sustainable printing methodologies.

In this Research, rheology characteristics have proven to be pivotal due to their direct influence on material flow and behaviour. Unlike conventional melting-based printing, where materials flow upon heating and solidify once they are extruded, ambient printing requires inks to have specific rheology behaviours caused by changes in shear. Rheology governs how easily the ink flows when extruded and its ability to retain shape once extruded. Optimizing the shear-thinning behaviour and elastic recovery behaviour is crucial. This study elaborates on the specific aspect of rheology to improve enhancements in print quality, including Yield stress, flow stress, storage modulus, loss tangent and thixotropic response and recovery. Additionally, it presents interesting insights into how to optimise them based on material composition and preparation. Mixing the material before extrusion, for example, was shown to significantly increase the thixotropic response time, leading to more precise extrusion.

Each year, 5.9 million tonnes of tea is consumed worldwide. However, this large consumption of tea also leads to large amounts of tea waste. Approximately 90% of steeped tea is being thrown away. This waste leads to problems such as environmental pollution. In order to combat this issue, Tea Clay was previously developed as a material made from wasted tea leaves. However, this material was not suitable for large scale implementation.

This project aims to explore the material-based opportunities for Tea Clay to be implemented on a larger scale.
The Tea Clay has an envisioned implementation as a memory board game based on tactile and olfactory senses for visually and non-visually impaired people. The Material Driven Design method is used for developing the material further to fit this vision. Benchmarking has inspired the material to have a reprocessing step: creating bulk material that can later be reprocessed into the intended product. Through tinkering, a new material with added gelatine and water was created which can reshape the material once it has been steamed. The reprocessability of the material could benefit the availability of the material for product implementation. Material can be created at one place and sold to customers, who in turn steam the material and reshape it in different products. The reprocessability also facilitates recyclability at the product end of life.

Bending tests and hardness tests have shown that it has a similar Young’s modulus and hardness as that of polypropylene and polyethylene, resulting in a material that is suitable for the substitution of conventional plastics. Experiential characterisation tests have proven that users are willing to interact with a novel material with appropriate background information. Knowing the material composition can stimulate them to be more accepting and embracing towards the material. Scent implementation is important for the intended product, as the scent should not disappear over time. A user test was conducted to test the scent duration and strength. Coating the material with essential oil has proven to keep the scent over a period of 4 weeks without much disappearance. The results of the material exploration both technically and experientially have come together in the design of a board game for visually and non-visually impaired people. This design aims at enhancing social interaction between visually and non-visually impaired through a game where everyone has a sense of collaboration and autonomy during game play and setup.

Overall, this study has demonstrated the potential of Tea Clay to be used as a waste composite material for product development. Future studies are still needed to further analyse the material properties of Tea Clay, and to validate its application in design for visually impaired people.

This graduation report describes the design of a new suitable menstruation product for Beppy that collects blood, is reusable, has a similar (deployable) size and function as a tampon, and which is perceived as less intimidating to insert and extract than a menstrual cup. The new design, the Beppy Clover, is made from silicone and has Nitinol, which is a shape memory alloy (SMA), wire embedded. Before insertion, the Clover has a diameter similar to a single use tampon by folding it in three sections. There is no constant external force needed to keep the Clover folded. Once the product is inserted and gets into contact with the body heat and blood in the vagina, the SMA wire (Af = 35°C) reacts and will return to its programmed shape. This results in the three sections with the SMA loops embedded deploying and adapting to the vagina canal. The product will stay in place, collect blood and after 8 hours or less, depending on the flow, can it be retracted by the loop or the attachable silicone extraction cord. The cleaning process works the same as a menstrual cup, rinsing between uses and sterilising at the beginning or end of the period.
To come to this final concept, an analysis, development and evaluation were performed. In the analysis, relevant information about the menstrual cycle, the dimensions of the vagina and current insertable (period) products is gathered. Furthermore, interviews with ten people were conducted to get insights into the user experience regarding their period and period products. At last, the materials and production methods of the Beppy cup are inspected, and new possible materials are looked at to integrate into the product, like shape memory alloy. This information is brought together in a list of requirements.
In the development, three main challenges are tackled: how to integrate deployment (1), insertion (2), and extraction (3) in the design, which would satisfy the requirements and, in particular, make it look less intimidating than a cup. Prototypes were made with silicones out of 3D printed moulds to test shapes, and the proof of concept of the composite of SMA wire with silicones was tested. A concept is made from the combinations of ideas and evaluated by three people focussing on perception and first impression of the Beppy Clover. With the feedback a final design is created.
The end result of the project is a promising final concept that could be the first step in the right direction regarding development of reusable blood collecting tampons. Utilising emerging materials was interesting to research its possibilities in period products. More tests and research on the combination of silicones and SMA wire reacting to body temperature will be necessary to optimise the force of the deployment of the product. Nevertheless, the Beppy Clover achieved its goal of being a blood collecting, reusable product that is perceived as less intimidating than the cup and has a similar (deployable) size and function as a tampon.

While Additive Manufacturing is famed for its ability to create complex geometries, sustainability of the technologies is given less attention. Due to the need to melt filament and heat up the printbed, FDM requires a considerable amount of energy. On top of that, valuable and non-renewable resources are used for the production of the commonly used filaments. There is a need for materials that are suitable for FDM printing, while being less detrimental for the environment than commonly used plastic filaments. In this project, paste-like material mixes are developed and tested for their suitability for FDM printing in order to see whether they have the potential to make FDM more sustainable.

Interwoven refers to material structures made by growing plant roots into man-made patterns. Originally developed as an art piece to demonstrate root intelligence and bring attention to human-nature relations, Interwoven shows the potential to disrupt various commercial industries, especially as textile-based natural fiber reinforcements for composite materials. The artist that created Interwoven, Amsterdam-based Diana Scherer, started a collaboration with the TU Delft Faculty of Industrial Design Engineering to help further develop Interwoven from an art piece to a sustainable material for products design. Following the Material Driven Design method (Karana, et al., 2015), two students have identified materials experience opportunities created by Interwoven materials, the mechanical properties and internal structure of Interwoven are still not fully understood.

This study tackles the challenge of performing a technical characterization on Interwoven structures in an effort to correlate processing parameters to its structure, properties, and performance. It is known from past works that Interwoven is fragile and “weak”, but a quantified value for these terms serves as a point of comparison with other materials in the market. To determine these values, a series of tensile tests were performed on grids with a simple square pattern. Dynamic Mechanical Analysis (DMA) tests performed on single roots proved that the amalgamation of roots that make up an Interwoven structure do not efficiently transfer tensile loads since the tensile strength and elastic moduli of Interwoven samples were nearly two orders of magnitude lower than those of a single root. Load transfer between roots was improved through the design of natural fiber-reinforced composites (NFRCs). The (bio)-polymer matrix used for these NFRCs was made up of agar gel, which improved the tensile properties of Interwoven samples, but was still lower than the single root.

A full characterization of a material correlates the observed properties to the structure of the material, which is done through the use of microscopy. Microscopic analyses were performed on all the tested samples to find any correlation between the observed tensile properties and the structure of Interwoven samples. In addition to providing insight about the complex interactions of roots as they form the patterns that they grow into, the microscopy also revealed that there is a direct correlation between the number of root tips (root endings) present at the intersection of squares in the grid and the mechanical properties of the sample.

With further research, this result can be tied to a parameter that the designer has direct control of, giving them better control of the properties of their Interwoven structures. Varying cell size in square patterns also allows designers to create structures with locally varying properties. The correlations between design parameters and material strength are summarized in the Guidelines to Designing with Interwoven booklet. A material demonstrator was also designed to showcase the locally variable mechanical properties in one structure while summarizing the test results in a way that is accessible and easy to understand.

The aim of this project was to get a better understanding of the shape memory behaviour of 3D-printed polymers, and the different parameters which affect this, with the ultimate goal to apply shape memory in product design. This project started with a literature study on shape memory polymers and 3D-printing. The material properties, different types of shape memory and different actuation methods were investigated, as well as different 3D-printing techniques and using shape memory polymers in 3D-printing. Existing applications and concepts using shape memory polymers, as well as recent studies in applying these materials were also investigated. In parallel to the literature study, testing was done on the influence of different parameters on the shape memory behaviour of one of the most common FDM 3D-printing materials: PLA. Through an iterative process, a test sample was designed which was used to test parameters related to material (different types of PLA), manufacturing (printing settings), and design (geometry and orientation of models). Knowledge gained through the literature research and testing was combined to create design guidelines for manufacturing shape memory objects using 3D-printing. To demonstrate how the shape memory capabilities of 3D-printed PLA could be applied in product design, A product concept was developed. With a vision as a starting point, ideation and concept development was started by first having a brainstorm session with different people to learn how people not involved with the project envisioned shape memory in product design. Moving on from this, useful results from this session were taken into an ideation phase, where a multitude of different ideas were thought up. From these ideas, four were chosen to be developed into concepts, of which one was chosen to be further developed into a physical prototype. The chosen concept was a wake-up light which uses the heat of the lightbulb inside the lamp to heat the shape memory material and initiate shape recovery, which resulted in the lamp gradually giving off more light. This would wake up the user in a natural way. The concept, which was given the name ‘’DAWN’’, was developed into a physical demonstrator, and the shape memory parts were printed based on the established guidelines. This also served as a test for the guidelines to see how they could be applied in the design process. After testing several printed prototype parts, a final design for the demonstrator was created and produced. At the end of the project, the process and results were evaluated and recommendations were given for further research into 3D-printing shape memory objects.

The goal of this study is to create a phantom which can be used to test strategies for sealing the vaginal cavity, so that ultrasound gel can be used to fill the vaginal cavity improve the visibility of the vaginal cavity in MR-images.
Silicone rubber and PolyVinyl Alcohol (PVA) were tested, to check whether their mechanical properties can be used to mimic the bio-mechanical behaviour of Human Anterior Vaginal Wall (HAVW)-tissue. Both materials were used to produce a phantom. Contrast differences in MR-imaging of PVA-hydrogel and silicone rubber with ultrasound gel and air were measured, to verify proper contrast within a phantom. Both phantoms were used to test sealing strategies.
Young's moduli for HAVW-tissue were obtained from literature, and formed a range (6.7 - 14.4 MPa). Silicon proved a closer match to the HAVW-tissue, compared to PVA-hydrogel. Calculated Young's moduli were between 1.4 - 4.2 MPa (silicone rubber) and 0.04 - 0.16 MPa (PVA-hydrogel). Contrast differences in MR-images were measured between 177.8 and 1585.7, and proved sufficient enough to be spotted by an untrained eye. The sealing strategies using a probe cover surrounding a catheter, showed an increase of 54.3% (silicone rubber) and 119.9% (PVA-hydrogel) of the filling percentage measured. Indentation testing was confirmed as a possible alternative to tensile testing for the verification of mechanical properties. In this study the production process of a thin-walled double-layered phantom of the vaginal cavity has been developed and tested. The developed phantoms have been used to test strategies for sealing the vaginal cavity. The concept using a catheter surrounded by a probe cover, is considered to improve the sealing of the vaginal cavity.

This thesis looks into the application of self-reinforced polypropylene (SRPP) in a tablet cover for the company Gecko Covers. Gecko Covers is a company that provides protection for devices in the form of covers and sleeves. They are performing at their best in the tablet market. They would like to enter the impact resistant tablet cover market using an impact cover that is both impact resistant and stylish. Their product style is characterized by the usage of contrast in both material texture and color, simple shapes and an attention to detail. Based on a market analysis, the tablet user on the go is selected as target group. These people carry their tablets with them wherever they go. To differentiate from the current competitors in this tablet market segment, Gecko has to focus on reducing the environmental impact of the new cover by e.g. making it recyclable. The most important material properties for the impact cover are high toughness, low density and a minimum ductile-to-brittle temperature of -20 °C. Not only does SRPP meet these requirements, it is also recyclable as it is only made out of a single type of thermoplastic. The manufacturing process of producing laminates out of woven SRPP influences the material properties such as impact resistance. Literature research shows that a combination of hot compaction and film stacking improves the impact resistance of the SRPP laminate the most. The values of the other parameters which influence the material properties of the laminates were determined through trial and error. To evaluate the SRPP laminates, a bending fatigue test and an alternative Izod impact test were conducted. In the end, the laminates with a compaction temperature of 170 °C, a pressure of 1,73 bar, an active heating time of 5 min and 1 PP film layer in between the SRPP fiber layer are the toughest and ductile. The focus of the design was on a minimum viable product. A back structure inspired by those of suitcases, the screen edge and the regular corners and edges of the cover were all taken into account. To validate that the shape is manufacturable from SRPP, a proof of concept was made with a mold. Furthermore, this proof of concept was tested via a drop test to get more information about the actual performance of the SRPP layer and to determine which orientation would have the highest impact resistance. The drop test showed the importance of the screen edge, which was missing from the proof of concept as it cannot be made out of SRPP. The test also showed that the SRPP lacked damping. To add the screen edge and the damping to the product, additional injection molded PP was used in order to add the screen edge and damping elements to the product. The final design was inspired by natural Voronoi structures and also creates a contrast in material texture and color, matching the current style of Gecko Covers.

Several underwater activities like exploration, surveillance, measuring key characteristics like water current or temperature, and mapping seabed risk human lives as the underwater conditions are hostile. Developing underwater vehicles provides a solution to minimize risking human lives. The underwater robots developed based on conventional actuation tend to be bulky and inefficient, lacking the ability to swim through a complex environment. Using smart materials, efficient robots can be built to swim individually or in swarms through a complex environment. However, there is a huge gap in the performance of the underwater robots developed using smart materials in comparison with the ones actuated conventionally. This thesis fills the gap by elaborating on the development of a robotic fish using polyvinylidene fluoride (PVDF), a smart material, that is proven to produce higher strain per volt among other electro-active polymers (EAPs). To develop a robotic fish, different swimming styles are studied and the carangiform style is adapted to achieve good efficiency without compromising maneuverability. The robotic fish is designed as a monolithic structure with an integrated actuator. The carangiform swimming style is implemented by designing a bi-morph actuator that occupies one-third portion of the robotic fish. The actuator is designed to produce symmetric tail deflections
in the lateral direction generating the vortices in the wake which can propel the robotic fish. In order to prove the usability of the actuator underwater, uni-morph actuators were manufactured using the inkjet printing technique. The actuator samples are developed on four different substrate materials, namely PEN, 25um Kapton, 50um Kapton, and Novele each with dimensions of 60mmx20.5mm. Experiments are conducted under various conditions to test their behavior before operating them underwater. The PVDF actuators developed using the Novele substrate successfully operated underwater at an operating frequency of 5.1Hz.

This booklet will take you on a journey into the world of shape memory alloys, by showing the explorative route I have taken. Although the road was not yet paved and sometimes very bumpy, I managed to reach my final goal. I am proud to present ThermoTilt, a responsive insulation layer which uses shape memory alloy’s unique properties to achieve its shape shifting abilities.