Review of Materials and Fabrication Methods for Flexible Nano and Micro-Scale Physical and Chemical Property Sensors

The use of flexible sensors has tripled over the last decade due to the increased demand in various fields including health monitoring, food packaging, electronic skins and soft robotics. Flexible sensors have the ability to be bent and stretched during use and can still maintain their electrical and mechanical properties. This gives them an advantage over rigid sensors that lose their sensitivity when subject to bending. Advancements in 3D printing have enabled the development of tailored flexible sensors. Various additive manufacturing methods are being used to develop these sensors including inkjet printing, aerosol jet printing, fused deposition modelling, direct ink writing, selective laser melting and others. Hydrogels have gained much attention in the literature due to their self-healing and shape transforming. Self-healing enables the sensor to recover from damages such as cracks and cuts incurred during use, and this enables the sensor to have a longer operating life and stability. Various polymers are used as substrates on which the sensing material is placed. Polymers including polydimethylsiloxane, Poly(N-isopropylacrylamide) and polyvinyl acetate are extensively used in flexible sensors. The most widely used nanomaterials in flexible sensors are carbon and silver due to their excellent electrical properties. This review gives an overview of various types of flexible sensors (including temperature, pressure and chemical sensors), paying particular attention to the application areas and the corresponding characteristics/properties of interest required for such. Current advances/trends in the field including 3D printing, novel nanomaterials and responsive polymers, and self-healable sensors and wearables will also be discussed in more detail.

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Review of Materials and Fabrication Methods for Flexible Nano and Micro-Scale Physical Property Sensors

10.20944/preprints202108.0351.v1 ◽

2021 ◽

Author(s):

Anesu Nyabadza ◽

Mercedes Vázquez ◽

Shirley Coyle ◽

Brian Fitzpatrick ◽

Dermot Brabazon

Keyword(s):

Food Packaging ◽

Physical Property ◽

Fused Deposition Modelling ◽

Self Healing ◽

Operating Life ◽

Flexible Sensors ◽

Fused Deposition ◽

Copper Manganese ◽

Jet Printing ◽

Aerosol Jet Printing

The use of flexible sensors has tripled over the last decade due to the increased demand in various fields including health monitoring, food packaging, electronic skins and soft robotics. Flexible sensors have the ability to be bent and stretched during use and can still maintain their electrical and mechanical properties. This gives them an advantage over rigid sensors that lose their sensitivity when subject to bending. Advancements in 3D printing have enabled the development of tailored flexible sensors. Various additive manufacturing methods are being used to develop these sensors including inkjet printing, aerosol jet printing, fused deposition modelling, direct ink writing, selective laser melting and others. Hydrogels have gained much attention in the literature due to their self-healing and shape transforming. Self-healing enables the sensor to recover from damages such as cracks and cuts incurred during use and this enables the sensor to have a longer operating life and stability. Various polymers are used as substrates on which the sensing conductive material is placed. Polymers including polydimethylsiloxane (PDMS), polyvinyl acetate (PVA), and Kapton are extensively used in flexible sensors. The most widely used nanomaterials in flexible sensors are carbon and silver, however, other nanomaterials such as iron, copper, manganese dioxide and gold are also used to provide controlled levels of conductivity or other functional properties.

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3D Printing of Solvent-Free Supramolecular Polymers

Frontiers in Chemistry ◽

10.3389/fchem.2021.771974 ◽

2021 ◽

Vol 9 ◽

Author(s):

Harald Rupp ◽

Wolfgang H. Binder

Keyword(s):

3D Printing ◽

Dynamic Properties ◽

Polymeric Materials ◽

Fundamental Principle ◽

Supramolecular Polymers ◽

Fused Deposition Modelling ◽

Self Healing ◽

Polymer Science ◽

Fused Deposition ◽

Molecular Ordering

Additive manufacturing has significantly changed polymer science and technology by engineering complex material shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve, e.g., self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing, can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in the 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FDM) to overcome some of its limitations still being present up to date and open perspectives for their application.

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3D Printing of a Self-Healing Thermoplastic Polyurethane through FDM: From Polymer Slab to Mechanical Assessment

Polymers ◽

10.3390/polym13020305 ◽

2021 ◽

Vol 13 (2) ◽

pp. 305

Author(s):

Linda Ritzen ◽

Vincenzo Montano ◽

Santiago J. Garcia

Keyword(s):

3D Printing ◽

Room Temperature ◽

Thermoplastic Polyurethane ◽

The Self ◽

Added Value ◽

Fused Deposition Modelling ◽

Full Potential ◽

Self Healing ◽

Fused Deposition ◽

3D Printed

The use of self-healing (SH) polymers to make 3D-printed polymeric parts offers the potential to increase the quality of 3D-printed parts and to increase their durability and damage tolerance due to their (on-demand) dynamic nature. Nevertheless, 3D-printing of such dynamic polymers is not a straightforward process due to their polymer architecture and rheological complexity and the limited quantities produced at lab-scale. This limits the exploration of the full potential of self-healing polymers. In this paper, we present the complete process for fused deposition modelling of a room temperature self-healing polyurethane. Starting from the synthesis and polymer slab manufacturing, we processed the polymer into a continuous filament and 3D printed parts. For the characterization of the 3D printed parts, we used a compression cut test, which proved useful when limited amount of material is available. The test was able to quasi-quantitatively assess both bulk and 3D printed samples and their self-healing behavior. The mechanical and healing behavior of the 3D printed self-healing polyurethane was highly similar to that of the bulk SH polymer. This indicates that the self-healing property of the polymer was retained even after multiple processing steps and printing. Compared to a commercial 3D-printing thermoplastic polyurethane, the self-healing polymer displayed a smaller mechanical dependency on the printing conditions with the added value of healing cuts at room temperature.

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Photocurable 3D Printing of High Toughness and Self‐Healing Hydrogels for Customized Wearable Flexible Sensors

Advanced Functional Materials ◽

10.1002/adfm.202107202 ◽

2021 ◽

pp. 2107202

Author(s):

Yuchao Wu ◽

Yong Zeng ◽

Yizhen Chen ◽

Chao Li ◽

Renhui Qiu ◽

...

Keyword(s):

3D Printing ◽

Self Healing ◽

Flexible Sensors ◽

High Toughness

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Advanced Pharmaceutical Applications of Hot-Melt Extrusion Coupled with Fused Deposition Modelling (FDM) 3D Printing for Personalised Drug Delivery

Pharmaceutics ◽

10.3390/pharmaceutics10040203 ◽

2018 ◽

Vol 10 (4) ◽

pp. 203 ◽

Cited By ~ 63

Author(s):

Deck Tan ◽

Mohammed Maniruzzaman ◽

Ali Nokhodchi

Keyword(s):

3D Printing ◽

Hot Melt Extrusion ◽

Pharmaceutical Products ◽

Fused Deposition Modelling ◽

Melt Extrusion ◽

3D Object ◽

3D Printing Technology ◽

Fused Deposition ◽

Pharmaceutical Applications ◽

Hot Melt

Three-dimensional printing, also known as additive manufacturing, is a fabrication process whereby a 3D object is created layer-by-layer by depositing a feedstock material such as thermoplastic polymer. The 3D printing technology has been widely used for rapid prototyping and its interest as a fabrication method has grown significantly across many disciplines. The most common 3D printing technology is called the Fused Deposition Modelling (FDM) which utilises thermoplastic filaments as a starting material, then extrudes the material in sequential layers above its melting temperature to create a 3D object. These filaments can be fabricated using the Hot-Melt Extrusion (HME) technology. The advantage of using HME to manufacture polymer filaments for FDM printing is that a homogenous solid dispersion of two or more pharmaceutical excipients i.e., polymers can be made and a thermostable drug can even be introduced in the filament composition, which is otherwise impractical with any other techniques. By introducing HME techniques for 3D printing filament development can improve the bioavailability and solubility of drugs as well as sustain the drug release for a prolonged period of time. The latter is of particular interest when medical implants are considered via 3D printing. In recent years, there has been increasing interest in implementing a continuous manufacturing method on pharmaceutical products development and manufacture, in order to ensure high quality and efficacy with less batch-to-batch variations of the pharmaceutical products. The HME and FDM technology can be combined into one integrated continuous processing platform. This article reviews the working principle of Hot Melt Extrusion and Fused Deposition Modelling, and how these two technologies can be combined for the use of advanced pharmaceutical applications.

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3D Printing of Thermo-Sensitive Drugs

Pharmaceutics ◽

10.3390/pharmaceutics13091524 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1524

Author(s):

Sadikalmahdi Abdella ◽

Souha H. Youssef ◽

Franklin Afinjuomo ◽

Yunmei Song ◽

Paris Fouladian ◽

...

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Fused Deposition Modelling ◽

Future Directions ◽

Digital Light Processing ◽

Fused Deposition ◽

Printing Technique ◽

3D Printed ◽

Semi Solid ◽

Selection Of

Three-dimensional (3D) printing is among the rapidly evolving technologies with applications in many sectors. The pharmaceutical industry is no exception, and the approval of the first 3D-printed tablet (Spiratam®) marked a revolution in the field. Several studies reported the fabrication of different dosage forms using a range of 3D printing techniques. Thermosensitive drugs compose a considerable segment of available medications in the market requiring strict temperature control during processing to ensure their efficacy and safety. Heating involved in some of the 3D printing technologies raises concerns regarding the feasibility of the techniques for printing thermolabile drugs. Studies reported that semi-solid extrusion (SSE) is the commonly used printing technique to fabricate thermosensitive drugs. Digital light processing (DLP), binder jetting (BJ), and stereolithography (SLA) can also be used for the fabrication of thermosensitive drugs as they do not involve heating elements. Nonetheless, degradation of some drugs by light source used in the techniques was reported. Interestingly, fused deposition modelling (FDM) coupled with filling techniques offered protection against thermal degradation. Concepts such as selection of low melting point polymers, adjustment of printing parameters, and coupling of more than one printing technique were exploited in printing thermosensitive drugs. This systematic review presents challenges, 3DP procedures, and future directions of 3D printing of thermo-sensitive formulations.

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On 3D printing of electro-active PVDF-Graphene and Mn-doped ZnO nanoparticle-based composite as a self-healing repair solution for heritage structures

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211060912 ◽

2021 ◽

pp. 095440542110609

Author(s):

Vinay Kumar ◽

Rupinder Singh ◽

Inderpreet Singh Ahuja

Keyword(s):

3D Printing ◽

Polyvinylidene Fluoride ◽

Nano Particles ◽

Zno Nanoparticle ◽

Self Healing ◽

Fused Deposition ◽

Crack Repair ◽

3D Printed ◽

Doped Zno ◽

Mn Doped

Construction is the part of human activity which is directly linked to urbanization for moving ahead on the path of growth and prosperity. Construction activities in past centuries are now part of our precious heritage. The repair and maintenance of heritage structures are of great importance for present-day researchers. One of the most common damage these century-long constructions faces are in form of surface cracks. In the present study, investigations were performed for a 3D printing-based customized solution for crack repair and maintenance of heritage structures. In this study, polyvinylidene fluoride (PVDF) polymer was reinforced with graphene (Gr) and Mn-doped ZnO nano-particles to prepare a smart composite material for crack repair and restoration. The composite was successfully 3D printed on fused deposition modeling (FDM) based 3D printer after investigating its rheological, thermal, and mechanical properties. The in-house developed composite was tested for smart characteristics to use as a programmable solution for filling cracks. The piezoelectric property and dielectric constant of 3D printed disk-shaped composite (PVDF-Gr-Mn-ZnO) were obtained after DC poling (to be used as stimulus) of the functional prototype. The results of the study suggest that the electro-active nature, volumetric change, and charge storing capacity of the additively manufactured composite may be used practically to acquire the shape of cavity/crack present in the constructed wall and repair the damages that occurred in a heritage site. The photoluminescence (PLS) and atomic force microscopy (AFM) analysis was used to ascertain the properties of the prepared composite. Also, the results obtained from the morphological analysis are reported to support the outcomes of the research.

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Use of polymer concrete for large-scale 3D printing

Rapid Prototyping Journal ◽

10.1108/rpj-12-2019-0316 ◽

2021 ◽

Vol 27 (3) ◽

pp. 465-474

Author(s):

Martin Krčma ◽

David Škaroupka ◽

Petr Vosynek ◽

Tomáš Zikmund ◽

Jozef Kaiser ◽

...

Keyword(s):

3D Printing ◽

Large Scale ◽

Mechanical Performance ◽

Construction Material ◽

Polymer Concrete ◽

Fused Deposition Modelling ◽

Cast State ◽

Content Type ◽

Fused Deposition ◽

3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

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Designing a delta tripod based robot fused deposition modelling 3 dimensional printer using an open-source Arduino development platform

MATEC Web of Conferences ◽

10.1051/matecconf/201818402013 ◽

2018 ◽

Vol 184 ◽

pp. 02013

Author(s):

Tamás Templom ◽

Timotei István Erdei ◽

Zsolt Molnár ◽

Edwin Shaw ◽

Géza Husi

Keyword(s):

3D Printing ◽

Rapid Prototyping ◽

Open Source ◽

Fused Deposition Modelling ◽

3 Dimensional ◽

Development Platform ◽

Fused Deposition

The pinnacle of 3D printing is its effect on the field of rapid prototyping. The major advantage comes from the fact that designers can quickly materialize a part or object, which then could be tested in practice, and can be effortlessly modified if needed. This obviously cuts the development expenses and time by a significant percent. Moreover, it’s possible to create complex and precise shapes with the technology, which would take more time and would be resource intensive if done by older methods, for example manual or automatic machining.

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Photonic curing of silver paths on 3D printed polymer substrate

Circuit World ◽

10.1108/cw-11-2018-0084 ◽

2019 ◽

Vol 45 (1) ◽

pp. 9-14

Author(s):

Jakub Krzeminski ◽

Bartosz Blicharz ◽

Andrzej Skalski ◽

Grzegorz Wroblewski ◽

Małgorzata Jakubowska ◽

...

Keyword(s):

Polymer Substrate ◽

Fused Deposition Modelling ◽

Content Type ◽

Fused Deposition ◽

Photonic Curing ◽

Structural Electronics ◽

Jet Printing ◽

3D Printed ◽

Aerosol Jet Printing ◽

Photonic Sintering

Purpose Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is a highly conductive material suitable for this technique. The purpose of this paper is to present the usage of the photonic curing process for sintering highly conductive paths printed on the polymer substrate. Design/methodology/approach This paper evaluates two photonic curing processes for the conductive network formulation during the additive manufacturing process. Along with the xenon flash sintering for aerosol jet-printed paths, this paper examines rapid infrared sintering for thick-film and direct write techniques. Findings This paper proves that the combination of fused deposition modeling, aerosol jet printing or paste deposition, along with photonic sintering, is suitable to obtain elements with low resistivity of 3,75·10−8 Ωm. Presented outcomes suggest the solution for fabrication of the structural electronics systems for daily-use applications. Originality/value The combination of fused deposition modelling (FDM) and aerosol jet printing or paste deposition used with photonic sintering process can fill the missing point for highly conductive materials for structural electronics.

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