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1 – 10 of 34Sena Demirbağ Genç and Sennur Alay-Aksoy
In this study, fabrication of polymer and cotton fabric exhibiting stimuli-responsive wetting and water vapor permeability features together with antibacterial activity was aimed.
Abstract
Purpose
In this study, fabrication of polymer and cotton fabric exhibiting stimuli-responsive wetting and water vapor permeability features together with antibacterial activity was aimed.
Design/methodology/approach
Temperature and pH-responsive poly(N-isopropyl acrylamide-graft-chitosan) (PNIPAM-g-CS) copolymer were produced via the free radical addition polymerization method and fixed to the cotton fabric using butane tetracarboxylic acid (BTCA) cross-linker by double-bath impregnation method. The chemical structure of the graft copolymer was characterized by Fourier-transform infrared spectroscopy (FT-IR) spectroscopy and H-Nuclear magnetic resonance (1H NMR) analyses. Thermo-responsive behavior of the fabric was investigated by wetting time and water uptake tests, contact angle measurement and surface energy calculation. Additionally, antibacterial activity of the fabric treated with copolymer was studied against S. aureus bacterium.
Findings
PNIPAM-g-CS graft copolymer was synthesized successfully, which had lower critical solution temperature (LCST) value of 32 °C and exhibited thermo-responsive property. The treated fabrics exhibited hydrophilic character at temperatures below the LCST and hydrophobic character at temperatures above the LCST. It was found that polymer-coated fabric could have regulated the water vapor permeability by the change in its pore size and hydrophilicity depending on the temperature. Additionally, treated fabric displayed a pH-responsive water absorption behavior and strong antibacterial activity against S.aureus bacterium.
Originality/value
In the study, it has been shown that the cotton fabrics can be fabricated which have antibacterial activity and capable of pH and temperature responsive smart moisture/water management by application of copolymer. It is thought that the fabric structures developed in the study will be promising in the production of medical textile structures where antibacterial activity and thermophysiological comfort are important.
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Gregory I. Peterson, Mete Yurtoglu, Michael B Larsen, Stephen L. Craig, Mark A. Ganter, Duane W. Storti and Andrew J. Boydston
This paper aims to explore and demonstrate the ability to integrate entry-level additive manufacturing (AM) techniques with responsive polymers capable of mechanical to chemical…
Abstract
Purpose
This paper aims to explore and demonstrate the ability to integrate entry-level additive manufacturing (AM) techniques with responsive polymers capable of mechanical to chemical energy transduction. This integration signifies the merger of AM and smart materials.
Design/methodology/approach
Custom filaments were synthesized comprising covalently incorporated spiropyran moieties. The mechanical activation and chemical response of the spiropyran-containing filaments were demonstrated in materials that were produced via fused filament fabrication techniques.
Findings
Custom filaments were successfully produced and printed with complete preservation of the mechanochemical reactivity of the spiropyran units. These smart materials were demonstrated in two key constructs: a center-cracked test specimen and a mechanochromic force sensor. The mechanochromic nature of the filament enables (semi)quantitative assessment of peak loads based on color change, without requiring any external analytical techniques.
Originality/value
This paper describes the first examples of three-dimensional-printed mechanophores, which may be of significant interest to the AM community. The ability to control the chemical response to external mechanical forces, in combination with AM to process the bulk materials, potentiates customizability at the molecular and macroscopic length scales.
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Aniqa Junaid, Murtaza Najabat Ali, Mariam Mir and Sadia Hassan
The purpose of this paper is to present synthesis protocol of hydrogel composed of Chitosan (CS) and Poly(ethylene glycol) (PEG) and establish an understanding of its thermal…
Abstract
Purpose
The purpose of this paper is to present synthesis protocol of hydrogel composed of Chitosan (CS) and Poly(ethylene glycol) (PEG) and establish an understanding of its thermal responsive behavior. It aims to prove the basic temperature sensing ability of a novel CS-PEG-based hydrogel and define its sensing span.
Design/methodology/approach
This study includes synthesis of CS and PEG-based hydrogel samples by first performing dissolution of both constituents, respectively, and then adding Glutaraldehyde as the cross-linking agent. It further includes proposed hydrogel’s swelling studies and dynamic behavior testing, followed by hydrogel characterization by Fourier transform infrared spectroscopy, X-ray diffraction and SEM. The last section focuses on the use of proposed hydrogel as a temperature sensor.
Findings
Detailed experimental results show that a hydrogel comprising of CS and PEG presents a thermally responsive behavior. It offers potential to be used as a temperature responsive hydrogel-based sensor which could be used in medical applications.
Originality/value
This research study presents scope for future research in the field of thermally responsive bio-sensors. It provides basis for the fabrication of a thermal responsive sensor system based on hydrogels that can be used in specific medical applications.
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Yu Chen, Irina Tatiana Garces, Tian Tang and Cagri Ayranci
The purpose of this paper is to demonstrate an innovative, fast and low-cost method to fabricate customized stents using polyurethane-based shape memory polymers composite…
Abstract
Purpose
The purpose of this paper is to demonstrate an innovative, fast and low-cost method to fabricate customized stents using polyurethane-based shape memory polymers composite reinforced by cellulose nanocrystal (CNC), achieved by a commercial desktop extrusion-based additive manufacturing (EBAM) device.
Design/methodology/approach
The composite filament for printing the stents was prepared by a two-step melt-compounding extrusion process. Afterward, the stents were produced by a desktop EBAM printer. Thermal characterizations, including thermo-gravimetric analysis (TGA) and modulated differential scanning calorimetry (modulated DSC), were conducted on stent samples and filament samples, respectively. Then the stents were programmed under 45°C. Recovery characterizations, including recovery force and recovery ratio measurement, were conducted under 40°C.
Findings
TGA results showed that the materials were stable under the printing temperature. Modulated DSC results indicated that, with the addition of CNCs, the glass transition temperature of the material dropped slightly from 39.7°C at 0 Wt.% CNC to 34.2°C at 7 Wt.% CNC. The recovery characterization showed that the stents can exert a maximum recovery force of 0.4 N/mm when 7 Wt.% of CNCs were added and the maximum recovery ratio of 35.8% ± 5.1% was found when 4 Wt.% of CNCs were added. The addition of CNC improved both the recovery ratio and the recovery force of the as-prepared stents.
Originality/value
In terms of recovery force, the as-prepared stents out-performed commercially available stents by 30 times. In addition, additive manufacturing offers more flexibility in the design and fabrication of customized cardiovascular stents.
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Ruoxuan Liu, Sean Mcginty, Fangsen Cui, Xiaoyu Luo and Zishun Liu
The purpose of this paper is to demonstrate the feasibility of using shape memory polymer (SMP) for developing vascular stent. In particular, the expansion performance is analyzed…
Abstract
Purpose
The purpose of this paper is to demonstrate the feasibility of using shape memory polymer (SMP) for developing vascular stent. In particular, the expansion performance is analyzed through extensive modeling and simulation.
Design/methodology/approach
Firstly, the authors construct the model geometry and propose a constitutive model to describe the deformation of the stent due to the expansion process. The authors then simulate the expansion process under varying conditions, including different heating rates and recovery temperatures. Finally, the authors analyze the radial strength of the SMP stent.
Findings
A less invasive and stable expansion performance of the SMP stent is confirmed by the simulation method. A fitting function of the expansion process is proposed based on the characteristics of the SMP.
Research limitations/implications
The effects of dynamic blood flow on the SMP stent is ignored. A fluid-structure interaction analysis may need to be considered to give a more accurate description of the behaviour of the SMP stent.
Practical implications
The findings will provide guidance for the rational design and application of SMP stents.
Social implications
The work will provide guidance for the new generation stent design.
Originality/value
This is the first time that the expansion performance of a SMP stent has been analyzed both qualitatively and quantitatively through modelling and simulation.
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H.B. Lu, W.M. Huang and Y.T. Yao
The purpose of this paper is to examine the underlying mechanism and physico‐chemical requirements of chemo‐responsive shape change/memory polymers and to explore the future trend…
Abstract
Purpose
The purpose of this paper is to examine the underlying mechanism and physico‐chemical requirements of chemo‐responsive shape change/memory polymers and to explore the future trend of development and potential applications.
Design/methodology/approach
Working mechanism in chemo‐responsive shape change/memory polymers is firstly identified. And then the physico‐chemical requirements for the representative polymers are characterized.
Findings
The different working mechanisms, fundamentals, physico‐chemical requirements and theoretical origins have been discussed. Current research and development on the fabrication strategies of chemo‐responsive shape change/memory polymers have been summarised. The future trend and potential applications have been explored and estimated.
Research limitations/implications
This review examines physico‐chemical requirements and theoretical origins necessary to achieve chemo‐responsiveness, and then discusses recent developments and future trends.
Practical implications
Shape change/memory polymers can be used in the broad field of bio‐ and/or medicine.
Originality/value
Breakthroughs and rapid development of chemo‐responsive shape change/memory polymers will significantly improve the research and development of smart materials, structures and systems.
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Xin Li, Jianzhong Shang and Zhuo Wang
The paper aims to promote the development of intelligent materials and the 4D printing technology by introducing recent advances and applications of additive layered manufacturing…
Abstract
Purpose
The paper aims to promote the development of intelligent materials and the 4D printing technology by introducing recent advances and applications of additive layered manufacturing (ALM) technology of intelligent materials and the development of the 4D printing technology. Also, an arm-type ALM technology of shape memory polymer (SMP) with thermosetting polyurethane is briefly introduced.
Design/methodology/approach
This paper begins with an overview of the development and applications of intelligent materials around the world and the 4D printing technology. Then, the authors provide a brief outline of their research on arm-type ALM technology of SMP with thermosetting polyurethane.
Findings
The paper provides the recent developments and applications of intelligent materials and 4D printing technology. Then, it is suggested that intelligent materials mixed with different functional materials will be developed, and these types of materials will be more suitable for 4D printing.
Originality/value
This paper overviews the current developments and applications of intelligent materials and its use in 4D printing technology, and briefly states the authors’ research on arm-type ALM technology of SMP with thermosetting polyurethane.
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Carlos Alejandro Garcia Rosales, Hoejin Kim, Mario F. Garcia Duarte, Luis Chavez, Tzu-Liang Bill Tseng and Yirong Lin
Shape memory polymers (SMPs) are classified as smart materials owing to their inherent stimulus-induced response. SMPs are capable of recovering partially or totally to its…
Abstract
Purpose
Shape memory polymers (SMPs) are classified as smart materials owing to their inherent stimulus-induced response. SMPs are capable of recovering partially or totally to its original shape after a high degree of deformation by external stimulus. The most used stimuli are thermal, light, magnetic field and electricity. This research aims to characterize the toughness property of thermo-responsive SMP specimens fabricated by the material extrusion (ME) process and to investigate the impact of ME parameters on specimen maximum load and load-displacement curves. Moreover, to investigate the recovery efficiency based on the initial and post toughness generated by the compact tension test.
Design/methodology/approach
A design of experiments with three parameters (temperature, velocity and layer height) defined the ME settings to fabricate the specimens. The ME raster orientation factor was also evaluated separately. In addition, one more specimen group assisted by a clamp during the recovery process was compared with a specimen control group. After fabrication, specimens were submitted to a thermo-mechanical cycle that encompasses a compact tension test and a thermo-recovery process. Comparison studies of load-displacement, toughness and recovery efficiency of the specimens were carried out to determine the optimized fabrication parameters.
Findings
It was found that ME parameters and raster orientation impacted the test results. Samples with the clamp support during recovery returned a higher toughness than samples without support. Finally, results showed that the shape memory effect can contribute with up to 43 per cent recovery efficiency in a first recovery and up to 23 per cent in a second recovery of damaged specimens.
Originality/value
This paper is a reference for toughness and recovery properties of SMP parts produced by the ME fabrication process.
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This study aims to present an architectural application of 4D-printed climate-adaptive kinetic architecture and parametric façade design.
Abstract
Purpose
This study aims to present an architectural application of 4D-printed climate-adaptive kinetic architecture and parametric façade design.
Design/methodology/approach
This work investigates experimental prototyping of a reversibly self-shaping façade, by integrating the parametric design approach, smart material and 4D-printing techniques. Thermo-responsive building skin modules of two-way shape memory composite (TWSMC) was designed and fabricated, combining the shape memory alloy fibers (SMFs) and 3D-printed shape memory polymer matrices (SMPMs). For geometry design, deformation of the TWSMC was simulated with a dimension-reduced mathematical model, and an optimal arrangement of three different types of TWSMC modules were designed and fabricated into a physical scale model.
Findings
Model-based experiments show robust workability and formal reversibility of the developed façade. Potential utility of this module for adaptive building design and construction is discussed based on the results. Findings help better understand the shape memory phenomena and presented design-inclusive technology will benefit architectural communities of smart climate-adaptive building.
Originality/value
Two-way reversibility of 4D-printed composites is a topic of active research in material science but has not been clearly addressed in the practical context of architectural design, due to technical barriers. This research is the first architectural presentation of the whole design procedure, simulation and fabrication of the 4D-printed and parametrically movable façade.
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L. Sun, W.M. Huang, H.B. Lu, C.C. Wang and J.L. Zhang
– This paper aims to present a review on utilizing shape memory technology (SMT) for active assembly/disassembly, i.e. assembly/disassembly without physically touching.
Abstract
Purpose
This paper aims to present a review on utilizing shape memory technology (SMT) for active assembly/disassembly, i.e. assembly/disassembly without physically touching.
Design/methodology/approach
The fundamentals behind the shape memory effect (SME) in materials, in particular shape memory alloys (SMAs) and polymers, which are the cornerstones of SMT, are introduced, together with the possible approaches to implement this effect in active assembly/disassembly. Example applications for not only active assembly/ disassembly, but also programmed active disassembly are presented.
Findings
The advantages of utilizing SMT over conventional assembly/disassembly techniques are identified.
Originality/value
The paper introduces the fundamentals behind the SME and the basic approaches to implement the SMT in not only active assembly/disassembly, but also programmed active assembly.
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