Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

► Journal Browser

Advances in Multifunctional Textiles: Materials, Technologies and Production Processes

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Advanced Composites".

Deadline for manuscript submissions: closed (10 August 2023) | Viewed by 19525

Share This Special Issue

Special Issue Editor

Prof. Dr. Jan Broda

E-Mail Website
Guest Editor

Faculty of Materials, Civil and Environmental Engineering, University of Bielsko-Biala, Willowa 2, 43-309 Bielsko-Biala, Poland
Interests: fiber structure; fiber morphology; polypropylene; crystallization; nucleating agents; pigment; wool; biodegradation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Textiles are a consumer good the consumption of which is systematically increasing. For centuries, textiles were used mainly in the apparel sector. In recent decades, however, the area of application of textiles has been extended significantly. In addition to classical products used in traditional applications, innovative household and technical textiles are constantly being developed.

Modern textiles have to face increasing development challenges to meet the criteria of sustainable development and fulfil highly technical, legal, and specific requirements. On the modern market, there is a growing demand for textiles presenting a multifunctional nature, which delivers more than one functionality apart from its primary function.

For the production of multifunctional textiles, novel materials and technologies are being conceived and developed. Numerous methods involve the application of new raw materials, adding nanoadditives modifying the fiber-forming polymers, grafting functional groups onto a polymer substrate, applying enzymes, cyclodextrines, and coating, using plasma, or loading various functional materials via micro- and nanoencapsulation, among others.

This Special Issue will compile the latest developments and innovations in the field of multifunctional textiles. The papers presented in this Special Issue will cover various topics connected with innovative materials, applied technologies, and production processes. It is my honor and pleasure to invite you to submit a manuscript to this Special Issue.

Prof. Dr. Jan Broda
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

textile finishing
nanoadditive
plasma treatment
encapsulation
grafting

Published Papers (12 papers)

Download All Papers

Research

17 pages, 7675 KiB

Open AccessArticle

Preparation of Bioactive Polyamide Fibres Modified with Acetanilide and Copper Sulphate

by Dorota Biniaś, Włodzimierz Biniaś, Czesław Ślusarczyk and Alicja Machnicka

Materials 2023, 16(20), 6789; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16206789 - 20 Oct 2023

Viewed by 768

Abstract

This paper presents a simple method of obtaining polyamide 6 fibres modified with acetanilide and copper ions. During the spinning of the fibres with the additives applied, a partial reduction of CuSO₄ to Cu²⁺ and Cu⁺ ions occurs, which is observed as a change in the blue colour of the prepared polyamide granulate to the grey–brown colour of the formed fibres. CuMPs obtained as a result of the salt reduction should give the obtained fibres bioactive properties. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against Gram-positive and Gram-negative bacteria. The largest inhibition zones were obtained for the Gram-positive bacteria Staphylococcus aureus, ranging from 1.5 to 4.5 mm, depending on the concentration of CuMPs. The morphology of the fibres’ surfaces was examined by means of scanning electron microscopy (SEM) and optical microscopy (OM). The changes in the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray structure studies (WAXS and SAXS) and an energy-dispersive spectroscopy (EDS) analysis. The newly obtained bioactive polyamide fibres can be used in many areas, including medicine, clothing and environmental protection for the production of filters. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Graphical abstract

25 pages, 14561 KiB

Open AccessArticle

Multi-Color Printed Textiles for Ultraviolet Radiation Measurements, Creative Designing, and Stimuli-Sensitive Garments

by Elżbieta Sąsiadek-Andrzejczak and Marek Kozicki

Materials 2023, 16(16), 5622; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16165622 - 14 Aug 2023

Viewed by 889

Abstract

This work concerns the new idea of textile printing with a multi-color system using pastes containing compounds sensitive to ultraviolet (UV) radiation. A screen printing method based on a modified CMYK color system was applied to a cotton woven fabric. Aqueous printing pastes were prepared from thickening and crosslinking agents and UV-sensitive compounds: leuco crystal violet (LCV), leuco malachite green (LMG), and 2,3,5-triphenyltetrazolium chloride (TTC) instead of the system’s standard process colors: cyan, magenta, and yellow. Depending on the number of printed layers and the type of UV radiation (UVA, UVB, and UVC), the modified textile samples change color after irradiation from white to a wide range of colors (from blue, red, and green to purple, brown, and gray). Based on reflectance measurements, the characteristic parameters of the one-, two-, and three-color-printed samples in relation to absorbed dose were determined, e.g., dose sensitivity, linear and dynamic dose response, and threshold dose. This printing method is a new proposal for UV dosimeters and an alternative standard for textile printing. Furthermore, the developed method can be used for the securing, marking, and creative design of textiles and opens up new possibilities for such stimulus-sensitive reactive printing. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Graphical abstract

15 pages, 6299 KiB

Open AccessArticle

Synthesis and Characterization of Pyridine Acetohydrazide Derivative for Antimicrobial Cotton Fabric

by Saeed El-Sayed Saeed, Meaad Aldubayyan, Ahmed N. Al-Hakimi and Marwa M. Abd El-Hady

Materials 2023, 16(13), 4885; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16134885 - 07 Jul 2023

Viewed by 795

Abstract

An increase in textile resistance to antimicrobial agents has posed a pressing need for the development of new antimicrobials. Therefore, the antimicrobial characteristics of thiophene and pyridine acetohydrazide derivatives have been developed as novel textile-modified complexes exhibiting antibacterial agents. Synthesis and characterization of pyridyl-thienyl acetohydrazide derivative (AHZ) using NMR (¹³C and ¹H) and FTIR. Modification of cotton fabric (CF) with acetohydrazide (AHZ) and metal chlorides of divalent Cr, Mn, Co, Ni, Cu, and Zn and trivalent Fe, and Cr. SEM-EDX and Fourier-transform infrared were utilized to characterize cellulose-based cotton fabric (CF) attached to AHZ and their metal (M) complexes. Antimicrobial activity was examined against two types of bacteria, namely S. aureus and E. coli, and two types of fungi, namely C. albicans and A. flavus. All modified samples exhibited higher efficiency towards bacterial strains than fungal strains. In addition, cellulose modified with Ni (II) confers the most antibacterial protection efficiency. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

18 pages, 76379 KiB

Open AccessArticle

Investigation of the Protective Function of a Lignin Coating of Natural Fiber Geotextiles against Biodegradation

by Cigdem Kaya, Thomas Stegmaier and Götz T. Gresser

Materials 2023, 16(13), 4849; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16134849 - 06 Jul 2023

Cited by 1 | Viewed by 1020

Abstract

Natural fibers do not have a long life in soil; therefore, they cannot replace synthetic textiles in many applications. However, in order to solve ever-increasing global environmental problems due to microplastics, more and more natural polymers must be used, creating a need for research into the sustainable life extension of natural fibers. Lignin is, along with cellulose, a main component of wood, and is produced in large quantities as waste during paper production. With appropriate processing, lignin can be exploited/used as a textile auxiliary to combine the strength-enhancing properties of textiles made from natural fibers with the protective properties of a lignin coating. However, there is not yet sufficient research on how to integrate lignin into textile applications. For this purpose, in this study, we have investigated whether thermoplastic lignin can be processed as a surface protective coating. We tested lignin as a yarn coating to extend the service life of cellulosic textiles. Cotton yarns have been coated with lignin in variations of coating mass, characterized and investigated by means of soil burial tests. As the soil burial tests conducted in climate chamber and outdoor field environments showed, the lifespan of textiles made from natural fibers can be significantly extended with a lignin coating. Long-term resilience has been demonstrated in standard burial tests. In the outdoor tests, the lignin coating was still fully intact, even after about 160 days of burial. The textile materials coated in this way enable sustainable applications, especially for geotextiles. They have an adjustable, sufficiently long service life; however, they are still biodegradable, and can therefore replace some applications, such as vegetating trench/brook slopes, with synthetic materials. Lignin-coated textiles have the potential to significantly reduce the carbon footprint, reduce not only the dependence on petroleum-based products but also the amount of microplastics entering the environment. Further research can be conducted to improve lignin compounding in terms of other interesting properties for specific textile applications. Process optimization could increase the protective effect and further extend the life of useful textiles in soil. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

18 pages, 6762 KiB

Open AccessArticle

GO-Enabled Bacterial Cellulose Membranes by Multistep, In Situ Loading: Effect of Bacterial Strain and Loading Pattern on Nanocomposite Properties

by Tobiasz Gabryś, Beata Fryczkowska, Urška Jančič, Janja Trček and Selestina Gorgieva

Materials 2023, 16(3), 1296; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16031296 - 02 Feb 2023

Cited by 1 | Viewed by 1510

Abstract

This paper presents the results of research on the preparation and properties of GO/BC nanocomposite from bacterial cellulose (BC) modified with graphene oxide (GO) using the in situ method. Two bacterial strains were used for the biosynthesis of the BC: Komagataeibacter intermedius LMG 18909 and Komagataeibacter sucrofermentans LMG 18788. A simple biosynthesis method was developed, where GO water dispersion was added to reinforced acetic acid-ethanol (RAE) medium at concentrations of 10 ppm, 25 ppm, and 50 ppm at 24 h and 48 h intervals. As a result, a GO/BC nanocomposite membrane was obtained, characterized by tensile strength greater by 150% as compared with the pure BC (̴ 50 MPa) and lower volume resistivity of ~4 ∙ 10⁹ Ω × cm. Moreover, GO addition increases membrane thickness up to ~10% and affects higher mass production, especially with low GO concentration. All of this may indicate the possibility of using GO/BC membranes in fuel cell applications. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

12 pages, 1550 KiB

Open AccessEditor’s ChoiceArticle

Effect of Blend Composition on Barrier Properties of Insulating Mats Produced from Local Wool and Waste Bast Fibres

by Anna Kicińska-Jakubowska, Jan Broda, Małgorzata Zimniewska, Marcin Bączek and Jerzy Mańkowski

Materials 2023, 16(1), 459; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16010459 - 03 Jan 2023

Cited by 3 | Viewed by 1548

Abstract

This paper concerns the management of natural waste fibres. The aim of this research was the production of multifunctional acoustic and thermal insulation materials from natural protein and lignocellulosic fibre wastes, according to a circular bioeconomy. For the manufacture of the materials, local mountain sheep wool and a mixture of bast fibre waste generated by string production were used. Insulating materials in the form of mats produced by the needle-punching technique with different fibre contents were obtained. The basic parameters of the mats, i.e., the thickness, surface weight and air permeability were determined. To assess barrier properties, sound absorption and noise reduction coefficients, as well as thermal resistance and thermal conductivity, were measured. It was shown that the mats exhibit barrier properties in terms of thermal and acoustic insulation related to the composition of the mat. It was found that mats with a higher content of the bast fibres possess a greater ability to absorb sounds, while mats with higher wool contents exhibit better thermal insulation properties. The produced mats can serve as a good alternative to commonly used acoustic and thermal insulating materials. The production of the described materials allows for a reduction in the amount of natural fibre waste and achieves the goal of “zero waste” according to the European Green Deal strategy. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

13 pages, 3743 KiB

Open AccessFeature PaperArticle

Multifunctional Geotextiles Produced from Reclaimed Fibres and Their Role in Ecological Engineering

by Damian Chmura, Anna Salachna, Jan Broda, Katarzyna Kobiela-Mendrek, Andrzej Gawłowski and Monika Rom

Materials 2022, 15(22), 7957; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15227957 - 10 Nov 2022

Cited by 1 | Viewed by 1227

Abstract

Earthworks in the vicinity of roads, open mines, subsidence tanks and other man-made objects can lead to the creation of slopes that undergo erosion. One of the methods that can prevent their degradation and reclaim them is the use of geotextiles. An environmentally friendly option is using geotextiles that are produced from reclaimed fibres. The purpose of this study was to examine the role of the mechanical and chemical properties of geotextiles, namely, ropes and fibres (containing wool and polypropylene), not only on the rate of the greening of slopes but also on the species composition of vegetation. We studied the floristic composition, species diversity, species growth and soil properties of four sites of reclaimed slopes on which 46 study plots (5 m × 5 m) were laid out. We found that some species were more confined to a higher content of wool and that other species were more confined to the content of polypropylene. Both materials caused a decrease in the Shannon–Wiener diversity but an increase in evenness under the impact of ropes when compared to the control. They both also contributed to a higher mean height of the plants when compared to the control. The rate of the plant colonisation process was markedly improved by the reclaimed geotextiles. A longer and more detailed study is required to examine the effect of geotextile ropes on habitat creation. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

25 pages, 10771 KiB

Open AccessArticle

Development of Piezoresistive Sensors Based on Graphene Nanoplatelets Screen-Printed on Woven and Knitted Fabrics: Optimisation of Active Layer Formulation and Transversal/Longitudinal Textile Direction

by Luisa M. Arruda, Inês P. Moreira, Usha Kiran Sanivada, Helder Carvalho and Raul Fangueiro

Materials 2022, 15(15), 5185; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15155185 - 26 Jul 2022

Cited by 10 | Viewed by 2254

Abstract

Although the force/pressure applied onto a textile substrate through a uniaxial compression is constant and independent of the yarn direction, it should be noted that such mechanical action causes a geometric change in the substrate, which can be identified by the reduction in its lateral thickness. Therefore, the objective of this study was to investigate the influence of the fabric orientation on both knitted and woven pressure sensors, in order to generate knowledge for a better design process during textile piezoresistive sensor development. For this purpose, these distinct textile structures were doped with different concentrations of graphene nanoplatelets (GNPs), using the screen-printing technique. The chemical and physical properties of these screen-printed fabrics were analysed using Field Emission Scanning Electron Microscopy, Ground State Diffuse Reflectance and Raman Spectroscopy. Samples were subjected to tests determining linear electrical surface resistance and piezoresistive behaviour. In the results, a higher presence of conductive material was found in woven structures. For the doped samples, the electrical resistance varied between 10⁵ Ω and 10¹ Ω, for the GNPs’ percentage increase. The lowest resistance value was observed for the woven fabric with 15% GNPs (3.67 ± 8.17 × 10¹ Ω). The samples showed different electrical behaviour according to the fabric orientation. Overall, greater sensitivity in the longitudinal direction and a lower coefficient of variation CV% of the measurement was identified in the transversal direction, coursewise for knitted and weftwise for woven fabrics. The woven fabric doped with 5% GNPs assembled in the weftwise direction was shown to be the most indicated for a piezoresistive sensor, due to its most uniform response and most accurate measure of mechanical stress. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

18 pages, 6299 KiB

Open AccessArticle

Impact of Low-Pressure Plasma Treatment of Wool Fabric for Dyeing with PEDOT: PSS

by Julija Petkevičiūtė, Audronė Sankauskaitė, Vitalija Jasulaitienė, Sandra Varnaitė-Žuravliova and Aušra Abraitienė

Materials 2022, 15(14), 4797; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15144797 - 08 Jul 2022

Cited by 2 | Viewed by 1603

Abstract

This study presents the effect of non-thermal plasma modification on the changes of surface morphology, color characteristics and electrical conductivity of wool fabric dyed with intrinsically conductive polymer (ICP) poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). The wool fabric was treated with an aqueous dispersion of PEDOT: PSS, Clevios F ET, providing electrically conductive properties to textiles. The wool fabric, containing basic groups of amines (NH₂), was pre-activated with low-pressure plasma of non-polymer forming nitrogen (N₂) gas before exhaust dyeing with PEDOT: PSS at 90 °C was applied. This treatment imparted hydrophilicity, reduced felting, increased adhesion, improved dye ability and ensured that more PEDOT: PSS negatively charged sulfonate

(- {SO}_{3} -)

counter ions would be electrostatically bounded with the cationic protonated amine groups of the wool fiber. Initially, before (N₂) plasma treatment and after fabrics were evaluated according to the test method for aqueous liquid repellency, the surface morphology of the plasma-modified and -unmodified wool dyed fabric was observed with scanning electron microscopy (SEM). The functional groups introduced onto the surface after N₂ gas plasma treatment of wool fabric were characterized by X-ray photoelectron and FTIR-ATR spectroscopy. The results of color difference measurements show that N₂ gas plasma treatments provide more intense color on Clevios F ET dyed wool fabric and retain its electrical conductivity. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

18 pages, 7015 KiB

Open AccessArticle

Quality and Quantity Assessment of the Water Repellent Properties of Functional Clothing Materials after Washing

by Mateusz Kowalski, Renata Salerno-Kochan, Irena Kamińska and Małgorzata Cieślak

Materials 2022, 15(11), 3825; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15113825 - 27 May 2022

Cited by 4 | Viewed by 1948

Abstract

The aim of the research was to evaluate the changes in the surface properties of five functional clothing materials with water-repellent finishes (including PFC-free finish) after 1, 5, and 10 washes with three detergents. A new approach to the interpretation of the water-repellent properties of textile materials is presented, based on two techniques, i.e., the spray test method and contact angle measurements. The results showed that washing materials with hydrophobic finishes can cause significant changes in their properties, which are mainly dependent on the composition and structure of the material, as well as the type of hydrophobic finish. The PFC-free finish is the least resistant to washing. For all materials with PFC finishes, the water repellency depends on the fluorine content on the surface and fabric topography. It was also found that increasing washing frequency resulted in a gradual decrease in water repellency. The loss of water repellency below an acceptable level (Grade 3) occurred after the fifth washing for all materials. Significant differences in the interpretation of the results of the spray test and contact angle measurements were observed. Using these methods separately provides information on the changes in the surface properties of the tested materials; however, their parallel application allows for obtaining complementary data, which is important for the proper interpretation of results. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

14 pages, 4703 KiB

Open AccessArticle

Acoustic Performance of Sound Absorbing Materials Produced from Wool of Local Mountain Sheep

by Katarzyna Kobiela-Mendrek, Marcin Bączek, Jan Broda, Monika Rom, Ingvild Espelien and Ingun Klepp

Materials 2022, 15(9), 3139; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15093139 - 26 Apr 2022

Cited by 12 | Viewed by 2482

Abstract

Wool of mountain sheep, treated nowadays as a waste or troublesome byproduct of sheep husbandry, was used for the production of sound-absorbing materials. Felts of two different thicknesses were produced from loose fibres. Additionally, two types of yarn, ring spun and core rug, were obtained. The yarns were used for the production of tufted fabric with cut and loop piles. During the examinations, basic parameters of the obtained materials were determined. Then, according to standard procedure with the use of impedance tube, the sound absorption coefficient was measured, and the noise reduction coefficient (NRC) was calculated. It was revealed that felt produced from coarse wool exhibits high porosity, and its sound absorbing capacity is strongly related to the felt thickness. For thicker felt the NRC achieved 0.4, which is comparable with the NRC of commercial ceiling tiles. It was shown that the crucial parameter influencing the sound absorption of the tufted fabrics was the pile height. For both types of yarns, when the height of the pile was increased from 12 to 16 mm, the NRC increased from 0.4 to 0.42. The manufactured materials made from local wool possess good absorption capacity, similar to commercial products usually made from more expensive wool types. The materials look nice and can be used for noise reduction as inner acoustic screens, panels, or carpets. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

22 pages, 11758 KiB

Open AccessArticle

The Influence of Electro-Conductive Compression Knits Wearing Conditions on Heating Characteristics

by Md. Reazuddin Repon, Ginta Laureckiene and Daiva Mikucioniene

Materials 2021, 14(22), 6780; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14226780 - 10 Nov 2021

Cited by 9 | Viewed by 2490

Abstract

Textile-based heaters have opened new opportunities for next-generation smart heating devices. This experiment presents electrically conductive textiles for heat generation in orthopaedic compression supports. The main goal was to investigate the influence of frequent washing and stretching on heat generation durability of constructed compression knitted structures. The silver coated polyamide yarns were used to knit a half-Milano rib structure containing elastomeric inlay-yarn. Dimensional stability of the knitted fabric and morphological changes of the silver coated electro-conductive yarns were investigated during every wash cycle. The results revealed that temperature becomes stable within two minutes for all investigated fabrics. The heat generation was found to be dependent on the stretching, mostly due to the changing surface area; and it should be considered during the development of heated compression knits. Washing negatively influences the heat-generating capacity on the fabric due to the surface damage caused by the mechanical and chemical interaction during washing. The higher number of silver-coated filaments in the electro-conductive yarn and the knitted structure, protecting the electro-conductive yarn from mechanical abrasion, may ensure higher durability of heating characteristics. Full article

(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advances in Multifunctional Textiles: Materials, Technologies and Production Processes

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (12 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI