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Material Characterization and Molecular Analysis of Polymeric Materials
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Material Characterization and Molecular Analysis of Polymeric Materials

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

Deadline for manuscript submissions: closed (10 September 2022) | Viewed by 7144

Special Issue Editor

Dr. Andrey E. Krauklis

E-Mail Website
Guest Editor
Institute for Mechanics of Materials, University of Latvia, Jelgavas Street 3, LV-1004 Riga, Latvia
Interests: modelling and analysis; materials science and engineering; physical chemistry; polymer science; composite materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Polymers occupy an important niche in the modern world’s broad choice of materials due to their highly varying range of their properties, both physical and chemical, among other factors. Such benefits, i.e., the “flexibility” in parameters, have ensured a wide range of applications for various polymeric materials.

This Special Issue aims to present a collection of multidisciplinary works involving experimental, mathematical and computational aspects of polymeric material characterization and molecular analysis. The scope includes pure polymers, plastics, composites as well as aged and/or modifications of the aforementioned materials and their derivatives. Various physical, chemical and biological characterization techniques and interpretations are welcome. Modelling approaches, such as quantitative structure–property relationships (QSPR), molecular dynamics (MD), finite element analysis (FEA), or novel machine learning (ML) tools are of particular interest, as are any approaches relevant to the Special Issue theme. Thus, the scope of the Special Issue spans across the whole modelling field and includes solutions based on mathematics, physics and chemistry (analytical, numerical and phenomenological tools).

We invite researchers to contribute to the Special Issue titled “Material Characterization and Molecular Analysis of Polymeric Materials”, which is intended to serve as a unique multidisciplinary forum for experimental, theoretical and computational science and engineering research.

Dr. Andrey E. Krauklis
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

  • material characterization
  • molecular analysis
  • polymers
  • modelling
  • multiscale models
  • polymer composites
  • quantitative structure–property relationships
  • finite element analysis
  • molecular dynamics
  • machine learning
  • Bayesian networks
  • computational property prediction and modelling

Published Papers (3 papers)

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Research

16 pages, 2287 KiB  
Article
The Activation Energy of Strain Bursts during Nanoindentation Creep on Polyethylene
by Mohammad Zare Ghomsheh and Golta Khatibi
Materials 2023, 16(1), 143; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16010143 - 23 Dec 2022
Viewed by 3566
Abstract
In the present investigation, statistical characterization of strain bursts observed during the load-controlled deformation of high-density polyethylene (HDPE), which arise within the crystalline phase during plastic deformation, was carried out via high-resolution nanoindentation creep experiments. Discrete deformation processes occurred during the nanoindentation creep [...] Read more.
In the present investigation, statistical characterization of strain bursts observed during the load-controlled deformation of high-density polyethylene (HDPE), which arise within the crystalline phase during plastic deformation, was carried out via high-resolution nanoindentation creep experiments. Discrete deformation processes occurred during the nanoindentation creep tests, which indicated that they arose from the break-off of dislocation avalanches, i.e., dislocation climb is a possible mechanism for indentation creep deformation. Characterization of the strain bursts, in terms of the associated height and number, demonstrated that these quantities followed a Gaussian distribution depending on the load and loading rate. This analysis enabled the accurate measurement of creep activation energy. Our method used nanoindentation tests to measure the creep activation energy of HDPE within both the crystalline and amorphous phases. The activation energy of the creep process within the crystalline phase was evaluated using two methods. The frequency of jumps within the crystalline phase, as a function of the strain rate, showed two peaks related to the 5 nm and 10 nm jump sizes that corresponded to the block size within the crystalline lamellae. The results indicated that the intervals coincided with the mean free path of dislocations and the block grain boundaries acted as dislocation barriers. From the dependence of burst frequency on the strain rate and temperature, the activation energy and thermally activated length of the dislocation segment for the plastic slip activation were determined to be 0.66 eV and 20 nm, respectively. Both numbers fit well to the Peterson’s model for the nucleation and motion of thermally activated dislocation segments. A similar activation energy resulted from the differential mechanical analysis of the literature for the αI—transition, which occurred near room temperature in polyethylene. The transition was described as the generation of screw dislocation and its motion along a block grain boundary; therefore, this process is suggested to be the basic mechanism underlying the strain bursts observed in this study. Full article
(This article belongs to the Special Issue Material Characterization and Molecular Analysis of Polymeric Materials)
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0 pages, 8173 KiB  
Article
An Investigation of the Thermal Transitions and Physical Properties of Semiconducting PDPP4T:PDBPyBT Blend Films
by Barbara Hajduk, Paweł Jarka, Tomasz Tański, Henryk Bednarski, Henryk Janeczek, Paweł Gnida and Mateusz Fijalkowski
Materials 2022, 15(23), 8392; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15238392 - 25 Nov 2022
Cited by 3 | Viewed by 1291
Abstract
This work focuses on the study of thermal and physical properties of thin polymer films based on mixtures of semiconductor polymers. The materials selected for research were poly [2,5-bis(2-octyldodecyl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2″;5″,2′′′-quater-thiophen-5,5′′′-diyl)]—PDPP4T, a p-type semiconducting polymer, and poly(2,5-bis(2-octyldodecyl)-3,6-di(pyridin-2-yl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-alt-2,2′-bithiophene)—PDBPyBT, a high-mobility n-type polymer. The article [...] Read more.
This work focuses on the study of thermal and physical properties of thin polymer films based on mixtures of semiconductor polymers. The materials selected for research were poly [2,5-bis(2-octyldodecyl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2″;5″,2′′′-quater-thiophen-5,5′′′-diyl)]—PDPP4T, a p-type semiconducting polymer, and poly(2,5-bis(2-octyldodecyl)-3,6-di(pyridin-2-yl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-alt-2,2′-bithiophene)—PDBPyBT, a high-mobility n-type polymer. The article describes the influence of the mutual participation of materials on the structure, physical properties and thermal transitions of PDPP4T:PDBPyBT blends. Here, for the first time, we demonstrate the phase diagram for PDPP4T:PDBPyBT blend films, constructed on the basis of variable-temperature spectroscopic ellipsometry and differential scanning calorimetry. Both techniques are complementary to each other, and the obtained results overlap to a large extent. Our research shows that these polymers can be mixed in various proportions to form single-phase mixtures with several thermal transitions, three of which with the lowest characteristic temperatures can be identified as glass transitions. In addition, the RMS roughness value of the PDPP4T:PDBPyBT blended films was lower than that of the pure materials. Full article
(This article belongs to the Special Issue Material Characterization and Molecular Analysis of Polymeric Materials)
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12 pages, 2932 KiB  
Article
Heparin-Loaded Alginate Hydrogels: Characterization and Molecular Mechanisms of Their Angiogenic and Anti-Microbial Potential
by Ayesha Nawaz, Sher Zaman Safi, Shomaila Sikandar, Rabia Zeeshan, Saima Zulfiqar, Nadia Mehmood, Hussah M. Alobaid, Fozia Rehman, Muhammad Imran, Muhammad Tariq, Abid Ali, Talha Bin Emran and Muhammad Yar
Materials 2022, 15(19), 6683; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15196683 - 26 Sep 2022
Cited by 8 | Viewed by 1820
Abstract
Background: Chronic wounds continue to be a global concern that demands substantial resources from the healthcare system. The process of cutaneous wound healing is complex, involving inflammation, blood clotting, angiogenesis, migration and remodeling. In the present study, commercially available alginate wound dressings were [...] Read more.
Background: Chronic wounds continue to be a global concern that demands substantial resources from the healthcare system. The process of cutaneous wound healing is complex, involving inflammation, blood clotting, angiogenesis, migration and remodeling. In the present study, commercially available alginate wound dressings were loaded with heparin. The purpose of the study was to enhance the angiogenic potential of alginate wound dressings and analyze the antibacterial activity, biocompatibility and other relevant properties. We also aimed to conduct some molecular and gene expression studies to elaborate on the mechanisms through which heparin induces angiogenesis. Methods: The physical properties of the hydrogels were evaluated by Fourier transform infrared spectroscopy (FTIR). Swelling ability was measured by soaking hydrogels in the Phosphate buffer at 37 °C, and cell studies were conducted to evaluate the cytotoxicity and biocompatibility of hydrogels in NIH3T3 (fibroblasts). Real-time PCR was conducted to check the molecular mechanisms of heparin/alginate-induced angiogenesis. The physical properties of the hydrogels were evaluated by Fourier transform infrared spectroscopy (FTIR). Results: FTIR confirmed the formation of heparin-loaded alginate wound dressing and the compatibility of both heparin and alginate. Among all, 10 µg/mL concentration of heparin showed the best antibacterial activity against E. coli. The swelling was considerably increased up to 1500% within 1 h. Alamar Blue assay revealed no cytotoxic effect on NIH3T3. Heparin showed good anti-microbial properties and inhibited the growth of E. coli in zones with a diameter of 18 mm. The expression analysis suggested that heparin probably exerts its pro-angiogenetic effect through VEGF and cPGE. Conclusions: We report that heparin-loaded alginate dressings are not cytotoxic and offer increased angiogenic and anti-bacterial potential. The angiogenesis is apparently taken through the VEGF pathway. Full article
(This article belongs to the Special Issue Material Characterization and Molecular Analysis of Polymeric Materials)
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