Polymers

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11 pages, 1932 KiB

Open AccessArticle

A Study of Wave Confinement and Optical Force in Polydimethlysiloxane–Arylazopyrazole Composite for Photonic Applications

by Ikemefuna Uba, Demetris Geddis, Kesete Ghebreyessus, Uwe Hömmerich and Jerald Dumas

Polymers 2022, 14(5), 896; https://doi.org/10.3390/polym14050896 - 24 Feb 2022

Cited by 3 | Viewed by 1378

Abstract

A refractive index of dielectrics was modified by several methods and was known to have direct influence on optical forces in nanophotonic structures. The present contribution shows that isomerization of photoswitching molecules can be used to regulate refractive index of dielectrics in-situ. In [...] Read more.

A refractive index of dielectrics was modified by several methods and was known to have direct influence on optical forces in nanophotonic structures. The present contribution shows that isomerization of photoswitching molecules can be used to regulate refractive index of dielectrics in-situ. In particular, spectroscopic study of a polydimethylsiloxane–arylazopyrazole (PDMS–AAP) composite revealed that refractive index of the composite shifts from 2.0 to 1.65 in trans and cis states, respectively, of the embedded AAP. Based on this, a proposition is made for a waveguide structure, in which external UV/Vis source reversibly regulates the conformation of the PDMS–AAP core. Computational study is performed using Maxwell’s equations on buried waveguide structure. The simulation, implemented in PYTHON, sequentially utilizes empirical refractive indices of the composite in the isomeric states in lieu of regulation by a source. The simulation revealed highly confined wave propagations for injected signals of 340 and 450 nm wavelengths. It is observed that the cis state suppresses higher order mode when propagating UV wavelength but allows it for visible light. This modal tuning demonstrated that single mode can be selectively excited with appropriate waveguide dimensions. Further impact of the tuning is seen in the optical force between waveguide pair where the forces shift between attractive and repulsive in relation to the isomeric state of the PDMS–AAP core. These effects which stem from the adjustment of refractive index by photoisomerization suggests that in-situ regulation of index is achievable by successful integration of photoswitching molecules in host materials, and the current PDMS–AAP composites investigated in this study can potentially enhance nanophotonic and opto-mechanical platforms. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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19 pages, 5019 KiB

Open AccessArticle

Eco-Geopolymers: Physico-Mechanical Features, Radiation Absorption Properties, and Mathematical Model

by Neslihan Doğan-Sağlamtimur, Ahmet Bilgil, Sefa Ertürk, Vakkas Bozkurt, Elif Süzgeç, Arife Gözde Akan, Pervin Nas, Hüseyin Çetin, Magdalena Szechyńska-Hebda and Marek Hebda

Polymers 2022, 14(2), 262; https://doi.org/10.3390/polym14020262 - 9 Jan 2022

Cited by 8 | Viewed by 2007

Abstract

Waste ashes and radiation are hazardous environmental and health factors; thus, a lot of attention is paid to their reduction. We present eco-geopolymer building materials (GPBMs) based on the class F fly ashes (FFAs) from thermal power plants (TPPs) and their implementation as [...] Read more.

Waste ashes and radiation are hazardous environmental and health factors; thus, a lot of attention is paid to their reduction. We present eco-geopolymer building materials (GPBMs) based on the class F fly ashes (FFAs) from thermal power plants (TPPs) and their implementation as a barrier against radioactive radiation. Different methods of production, ratios of FFA to alkali activator, and temperatures of curing were tested. Small spherical particles and higher content of SiO₂ resulted in developed surface area and higher reactivity of Isken TPP FFA than Catalagzi TPP FFA. Lower activator concentration (10% vs. 20%) and curing temperature (70 vs. 100 °C) caused an increase in GPBM compressive strength; the highest value was measured as 93.3 MPa. The highest RA was measured for GPBMs, provided alkali activator ratio (Na₂SiO₃/NaOH) was >2 and its concentration was 20%. The mathematical model developed in this study proved FFA quantity, and thus GPBM mechanical properties, as key factors influencing RA. In the light of these results, the lightweight GPBMs can be excellent materials for the construction sector dedicated to immobilization, storage, and disposal for radionuclides or barriers against radiation; however, multiple steps of their production require careful optimization. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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18 pages, 6060 KiB

Open AccessArticle

Microencapsulation of Curcumin in Crosslinked Jelly Fig Pectin Using Vacuum Spray Drying Technique for Effective Drug Delivery

by Nina Hartini, Thangavel Ponrasu, Jia-Jiuan Wu, Malinee Sriariyanun and Yu-Shen Cheng

Polymers 2021, 13(16), 2583; https://doi.org/10.3390/polym13162583 - 4 Aug 2021

Cited by 19 | Viewed by 3302

Abstract

Microencapsulation of curcumin in jelly fig pectin was performed by the vacuum spray drying (VSD) technique. The VSD was advanced with a low inlet temperature of 80–90 °C and low pressure of 0.01 mPa. By the in situ cross-linking with multivalent calcium ions, [...] Read more.

Microencapsulation of curcumin in jelly fig pectin was performed by the vacuum spray drying (VSD) technique. The VSD was advanced with a low inlet temperature of 80–90 °C and low pressure of 0.01 mPa. By the in situ cross-linking with multivalent calcium ions, jelly fig pectin produced stable curcumin encapsulated microparticles. The physiochemical characteristics of microparticles were thoroughly investigated. The results revealed that 0.75 w/w% of jelly fig pectin and inlet temperature of 90 °C could be feasible for obtaining curcumin microparticles. The VSD technique showed the best encapsulation efficiency and yield and loading efficiency was up to 91.56 ± 0.80%, 70.02 ± 1.96%, and 5.45 ± 0.14%, respectively. The curcumin was readily released into simulated gastrointestinal fluid with 95.34 ± 0.78% cumulative release in 24 h. The antioxidant activity was stable after being stored for six months and stored as a solution for seven days at room temperature before analysis. Hence, the VSD technique could be applicable for the microencapsulation of bioactive compounds such as curcumin to protect and use in the food/pharmaceutical industry. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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12 pages, 3299 KiB

Open AccessArticle

Investigation of Flexible Arrayed Lactate Biosensor Based on Copper Doped Zinc Oxide Films Modified by Iron–Platinum Nanoparticles

by Yu-Hsun Nien, Zhi-Xuan Kang, Tzu-Yu Su, Chih-Sung Ho, Jung-Chuan Chou, Chih-Hsien Lai, Po-Yu Kuo, Tsu-Yang Lai, Zhe-Xin Dong, Yung-Yu Chen and Yu-Hao Huang

Polymers 2021, 13(13), 2062; https://doi.org/10.3390/polym13132062 - 23 Jun 2021

Cited by 15 | Viewed by 2757

Abstract

Potentiometric biosensors based on flexible arrayed silver paste electrode and copper-doped zinc oxide sensing film modified by iron-platinum nanoparticles (FePt NPs) are designed and manufactured to detect lactate in human. The sensing film is made of copper-doped zinc oxide (CZO) by a radio [...] Read more.

Potentiometric biosensors based on flexible arrayed silver paste electrode and copper-doped zinc oxide sensing film modified by iron-platinum nanoparticles (FePt NPs) are designed and manufactured to detect lactate in human. The sensing film is made of copper-doped zinc oxide (CZO) by a radio frequency (RF) sputtering system, and then modified by iron-platinum nanoparticles (FePt NPs). The surface morphology of copper-doped zinc oxide (CZO) is analyzed by scanning electron microscope (SEM). FePt NPs are analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The average sensitivity, response time, and interference effect of the lactate biosensors are analyzed by voltage-time (V-T) measurement system. The electrochemical impedance is analyzed by electrochemical impedance spectroscopy (EIS). The average sensitivity and linearity over the concentration range 0.2–5 mM are 25.32 mV/mM and 0.977 mV/mM, respectively. The response time of the lactate biosensor is 16 s, with excellent selectivity. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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14 pages, 3209 KiB

Open AccessArticle

Fabrication and Characterization of Nylon 66/PAN Nanofibrous Film Used as Separator of Lithium-Ion Battery

by Yu-Hsun Nien, Chih-Ning Chang, Pao-Lin Chuang, Chun-Han Hsu, Jun-Lun Liao and Chen-Kai Lee

Polymers 2021, 13(12), 1984; https://doi.org/10.3390/polym13121984 - 17 Jun 2021

Cited by 12 | Viewed by 2678

Abstract

In recent years, portable electronic devices have flourished, and the safety of lithium batteries has received increasing attention. In this study, nanofibers were prepared by electrospinning using different ratios of nylon 66/polyacrylonitrile (PAN), and their properties were studied and compared with commercial PP [...] Read more.

In recent years, portable electronic devices have flourished, and the safety of lithium batteries has received increasing attention. In this study, nanofibers were prepared by electrospinning using different ratios of nylon 66/polyacrylonitrile (PAN), and their properties were studied and compared with commercial PP separators. The experimental results show that the addition of PAN in nylon 66/PAN nanofibrous film used as separator of lithium-ion battery can enhance the porosity up to 85%. There is also no significant shrinkage in the shrinkage test, and the thermal dimensional stability is good. When the Li/LiFePO₄ lithium battery is prepared by nylon 66/PAN nanofibrous film used as separator, the capacitor can be maintained at 140 mAhg⁻¹ after 20 cycles at 0.1 C, and the coulombic efficiency is still maintained at 99%, which has excellent electrochemical performance. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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18 pages, 43693 KiB

Open AccessArticle

Electrodeposited Copolymers Based on 9,9′-(5-Bromo-1,3-phenylene)biscarbazole and Dithiophene Derivatives for High-Performance Electrochromic Devices

by Chung-Wen Kuo, Jui-Cheng Chang, Jeng-Kuei Chang, Sheng-Wei Huang, Pei-Ying Lee and Tzi-Yi Wu

Polymers 2021, 13(7), 1136; https://doi.org/10.3390/polym13071136 - 2 Apr 2021

Cited by 6 | Viewed by 2110

Abstract

A 1,3-bis(carbazol-9-yl)benzene derivative (BPBC) was synthesized and its related homopolymer (PBPBC) and copolymers (P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK)) were prepared using electrochemical polymerization. Investigations of polymeric spectra showed that PBPBC film was grey, iron-grey, yellowish-grey, and greyish-green from [...] Read more.

A 1,3-bis(carbazol-9-yl)benzene derivative (BPBC) was synthesized and its related homopolymer (PBPBC) and copolymers (P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK)) were prepared using electrochemical polymerization. Investigations of polymeric spectra showed that PBPBC film was grey, iron-grey, yellowish-grey, and greyish-green from the neutral to the oxidized state. P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK) films showed multicolor transitions from the reduced to the oxidized state. The transmittance change (ΔT) of PBPBC, P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK) films were 29.6% at 1040 nm, 44.4% at 1030 nm, 22.3% at 1050 nm, and 41.4% at 1070 nm. The coloration efficiency (η) of PBPBC and P(BPBC-co-CDTK) films were evaluated to be 140.3 cm² C⁻¹ at 1040 nm and 283.7 cm² C⁻¹ at 1070 nm, respectively. A P(BPBC-co-BT)/PEDOT electrochromic device (ECD) showed a large ΔT (36.2% at 625 nm) and a fast response time (less than 0.5 s), whereas a P(BPBC-co-CDTK)/PEDOT ECD revealed a large η (534.4 cm² C^–1 at 610 nm) and sufficient optical circuit memory. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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16 pages, 4353 KiB

Open AccessArticle

Encapsulation and Characterization of Nanoemulsions Based on an Anti-oxidative Polymeric Amphiphile for Topical Apigenin Delivery

by Tzung-Han Chou, Daniel Setiyo Nugroho, Jia-Yaw Chang, Yu-Shen Cheng, Chia-Hua Liang and Ming-Jay Deng

Polymers 2021, 13(7), 1016; https://doi.org/10.3390/polym13071016 - 25 Mar 2021

Cited by 22 | Viewed by 3386

Abstract

Apigenin (Apig) is used as a model drug due to its many beneficial bio-activities and therapeutic potentials. Nevertheless, its poor water solubility and low storage stability have limited its application feasibility on the pharmaceutical field. To address this issue, this study developed nanoemulsions [...] Read more.

Apigenin (Apig) is used as a model drug due to its many beneficial bio-activities and therapeutic potentials. Nevertheless, its poor water solubility and low storage stability have limited its application feasibility on the pharmaceutical field. To address this issue, this study developed nanoemulsions (NEs) using an anti-oxidative polymeric amphiphile, d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), hydrogenated soy lecithin (HL), black soldier fly larvae (BSFL) oil, and avocado (AV) oil through pre-homogenization and ultrasonication method. Addition of TPGS (weight ratios 100 and 50% as compared to HL) into NEs effectively reduced particle size and phase transition region area of NEs with pure HL. Incorporation of Apig into NEs made particle size increase and provided a disorder effect on intraparticle molecular packing. Nevertheless, the encapsulation efficiency of NEs for Apig approached to about 99%. The chemical stability of Apig was significantly improved and its antioxidant ability was elevated by incorporation with BSFL oil and AV oil NEs, especially for NEs with single TPGS. NEs with single TPGS also exhibited the best Apig skin deposition. For future application of topical Apig delivery, NEs-gel was formed by the addition of hyaluronic acid (HA) into NEs. Their rheological characteristics were dominated by the surfactant ratios of HL to TPGS. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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13 pages, 5021 KiB

Open AccessArticle

Novel Terahertz Spectroscopy Technology for Crystallinity and Crystal Structure Analysis of Cellulose

by Rui Yang, Xianyin Dong, Gang Chen, Feng Lin, Zhenhua Huang, Maurizio Manzo and Haiyan Mao

Polymers 2021, 13(1), 6; https://doi.org/10.3390/polym13010006 - 22 Dec 2020

Cited by 12 | Viewed by 3370

Abstract

Crystallinity is an essential indicator for evaluating the quality of fiber materials. Terahertz spectroscopy technology has excellent penetrability, no harmful substances, and commendable detection capability of absorption characteristics. The terahertz spectroscopy technology has great application potential in the field of fiber material research, [...] Read more.

Crystallinity is an essential indicator for evaluating the quality of fiber materials. Terahertz spectroscopy technology has excellent penetrability, no harmful substances, and commendable detection capability of absorption characteristics. The terahertz spectroscopy technology has great application potential in the field of fiber material research, especially for the characterization of the crystallinity of cellulose. In this work, the absorption peak of wood cellulose, microcrystalline cellulose, wood nano cellulose, and cotton nano cellulose were probed in the terahertz band to calculate the crystallinity, and the result compared with XRD and FT-IR analysis. The vibration model of cellulose molecular motion was obtained by density functional theory. The results showed that the average length of wood cellulose (WC) single fiber was 300 μm. The microcrystalline cellulose (MCC) was bar-like, and the average length was 20 μm. The cotton cellulose nanofiber (C-CNF) was a single fibrous substance with a length of 50 μm, while the wood cellulose nanofiber (W-CNF) was with a length of 250 μm. The crystallinity of cellulose samples in THz was calculated as follows: 73% for WC, 78% for MCC, 85% for W-CNF, and 90% for C-CNF. The crystallinity values were obtained by the three methods which were different to some extent. The absorption peak of the terahertz spectra was most obvious when the samples thickness was 1 mm and mixed mass ratio of the polyethylene and cellulose was 1:1. The degree of crystallinity was proportional to the terahertz absorption coefficients of cellulose, the five-movement models of cellulose molecules corresponded to the five absorption peak positions of cellulose. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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Review

Jump to: Research

28 pages, 4290 KiB

Open AccessReview

Product Development of Natural Fibre-Composites for Various Applications: Design for Sustainability

by Muhammad Rizal Muhammad Asyraf, Agusril Syamsir, Nazirul Mubin Zahari, Abu Bakar Mohd Supian, Mohamad Ridzwan Ishak, Salit Mohd Sapuan, Shubham Sharma, Ahmad Rashedi, Muhammad Rizal Razman, Sharifah Zarina Syed Zakaria, Rushdan Ahmad Ilyas and Mohamad Zakir Abd Rashid

Polymers 2022, 14(5), 920; https://doi.org/10.3390/polym14050920 - 25 Feb 2022

Cited by 64 | Viewed by 6231

Abstract

New product development review article aims to consolidate the principles and current literature on design for sustainability to seek the field’s future direction. In this point of view, the design for sustainability methods can be established under the idea of sustainability in dimensions [...] Read more.

New product development review article aims to consolidate the principles and current literature on design for sustainability to seek the field’s future direction. In this point of view, the design for sustainability methods can be established under the idea of sustainability in dimensions of ecology, economy and social pillars. Design for sustainability concept is implemented in concurrent engineering, including concept, embodiment and detail design processes. Integrating sustainability in engineering designs is crucial to producing greener products, system innovation, and services aligned with current market demand. Currently, many concurrent engineering studies related to natural fibre-reinforced polymer composites associated with sustainability enhance the application of design for sustainability techniques by professional designers. However, the current literature is scarce in bridging the design for sustainability concept with concurrent engineering during the design development stage, and these areas should be further developed. Several other future research directions, such as the need for aligning with principles and applications, along with exploring the relationships between the design for sustainability techniques and views of sustainability, are presented in this review paper. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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13 pages, 4782 KiB

Open AccessReview

Recent Advances in Environmentally Friendly and Green Degumming Processes of Silk for Textile and Non-Textile Applications

by Lei Zhu, Junxiong Lin, Liujun Pei, Yuni Luo, Dali Li and Zhichao Huang

Polymers 2022, 14(4), 659; https://doi.org/10.3390/polym14040659 - 9 Feb 2022

Cited by 32 | Viewed by 4603

Abstract

Silk has been widely used not only in the textile field but also in non-textile applications, which is composed of inner fibrous protein, named fibroin, and outer global protein, named sericin. Due to big differences, such as appearance, solubility, amino acid composition and [...] Read more.

Silk has been widely used not only in the textile field but also in non-textile applications, which is composed of inner fibrous protein, named fibroin, and outer global protein, named sericin. Due to big differences, such as appearance, solubility, amino acid composition and amount of reactive groups, silk fibroin and sericin usually need to be separated before further process. The residual sericin may influence the molecular weight, structure, morphology and properties of silk fibroin, so that degumming of silk is important and necessary, not only in textile field but also in non-textile applications. Traditional textile degumming processes, including soap, alkali or both, could bring such problems as environmental damage, heavy use of water and energy, and damage to silk fibroin. Therefore, this review aims to present a systematic work on environmentally friendly and green degumming processes of raw silk, including art of green degumming process, quantitative and qualitative evaluation, influence of degumming on molecular weight, structure, morphology and properties of silk. It is anticipated that rational selection and design of environmentally friendly and green degumming process is quite important and meaningful, not only for textile application but also for non-textile application. Full article

(This article belongs to the Special Issue Advances in Functional Polymeric Materials)

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