Phase Behavior in Polymers: Morphology and Self-Assembly

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Analysis and Characterization".

Deadline for manuscript submissions: closed (20 January 2023) | Viewed by 9706

Special Issue Editor


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Guest Editor
Department of Chemical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701-01, Taiwan
Interests: polymer crystallization and morphology; self-assembly; photonic crystals; biodegradable polymers; nanocomposites
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Special Issue Information

Dear Colleagues,

Polymers are made of repeating units—monomers of a variety of structures. Thus, architects of polymer structures influence phase behavior in many aspects. Polymers of different structures (variations in monomer types, Mw, copolymerization, branching, crosslinking, etc.) can display phase behavior in many ways. Furthermore, polymers can be blended/mixed with other polymers or low-Mw compounds or solvents to display even wider and complex myriads of phase behavior. The phase behavior of polymers, in turn, can influence the physical and mechanical properties for ultimate applications. In wider scopes, polymers with semicrystalline structures contain at least two phases: Crystalline and amorphous domains and their crystal-assembled morphologies also determine their applications. Although fundamentals of polymer phase behavior in polymers, blends, and block copolymers have been widely studied, well understood, and soundly established in the past few decades, recent significant advances in polymer self-assembly, supramolecular architects, photonics, biomimetics and biomedical fields, etc., demand a Special Issue.

This Special Issue, “Phase Behavior in Polymers: Morphology and Self-Assembly”, will be a collection of high-caliber original/review papers focusing on recent progress in the following topics: (a) polymer crystal-amorphous phases in bulks or thin films; (b) binary-ternary homopolymer mixtures/blends and diblock/triblock copolymers exhibiting macrophase/microphase separation and phase-domain morphology; (c) polymer phase separation/crystallization for photonics properties; (d) novel interpretations for phase separation or crystallization in polymers, copolymers, or blends; and (e) special phase behavior or surface-relief periodic patterns of polymers, blends or polymer–polymer complexes with potential applications as biomimetics, functional, biomedical, or photonic applications.

Although other potentially interesting topics are also welcome and not limited to the above lists, intended submissions should fall generally in line with phase behavior in polymers.

Prof. Dr. Eamor Woo
Guest Editor

Manuscript Submission Information

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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. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

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Keywords

  • Phase behavior of blends or copolymers
  • Crystallization induced separation
  • Morphology
  • Self-assembly and surface relief patterns
  • Supramolecular architect

Published Papers (5 papers)

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Research

16 pages, 22266 KiB  
Article
Synergy of Fiber Surface Chemistry and Flow: Multi-Phase Transcrystallization in Fiber-Reinforced Thermoplastics
by Stan F. S. P. Looijmans, Michelle M. A. Spanjaards, Ljiljana Puskar, Dario Cavallo, Patrick D. Anderson and Lambèrt C. A. van Breemen
Polymers 2022, 14(22), 4850; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14224850 - 10 Nov 2022
Cited by 2 | Viewed by 1259
Abstract
Fiber-reinforced polymer composites are largely employed for their improved strength with respect to unfilled matrices. Considering semi-crystalline materials under relevant processing conditions, the applied pressure and flow induce shear stresses at the fiber–polymer interface. These stresses may strongly enhance the nucleation ability of [...] Read more.
Fiber-reinforced polymer composites are largely employed for their improved strength with respect to unfilled matrices. Considering semi-crystalline materials under relevant processing conditions, the applied pressure and flow induce shear stresses at the fiber–polymer interface. These stresses may strongly enhance the nucleation ability of the fiber surface with respect to the quiescent case. It is thus possible to assume that the fiber features are no longer of importance and that crystallization is dominated by the effect of flow. However, by making use of an advanced experimental technique, i.e., polarization-modulated synchrotron infrared microspectroscopy (PM-SIRMS), we are able to show that the opposite is true for the industrially relevant case of isotactic polypropylene (iPP). With PM-SIRMS, the local chain orientation is measured with micron-size spatial resolution. This orientation can be related to the polymer nucleation density along the fiber surface. For various combinations of an iPP matrix and fiber, the degree of orientation in the cylindrical layer that develops during flow correlates well with the differences in nucleation density found in quiescent conditions. This result shows that the morphological development during processing of polymer composites is not solely determined by the flow field, nor by the nucleating ability of the fiber surface alone, but rather by a synergistic combination of the two. In addition, using finite element modeling, it is demonstrated that, under the experimentally applied flow conditions, the interphase structure formation is mostly dominated by the rheological characteristics of the material rather than perturbations in experimental conditions, such as shear rate, layer thickness, and temperature. This once again highlights the importance of matrix–filler interplay during flow and, thus, of material selection in the design of hybrid and lightweight composite technologies. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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16 pages, 5370 KiB  
Article
Water Sorption by Polyheteroarylenes
by Anatoly E. Chalykh, Tatiana F. Petrova and Igor I. Ponomarev
Polymers 2022, 14(11), 2255; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14112255 - 31 May 2022
Cited by 2 | Viewed by 1159
Abstract
The sorption–diffusion characteristics of rigid-chain glassy polymers based on polyheteroarylenes (PHAs) have been studied in a wide interval of relative humidity and temperatures of thermal treatment of the polymer sorbents. Experimental data on water vapor sorption for polynaphthoyleneimidobenzimidazole (PNIB) and its copolymers with [...] Read more.
The sorption–diffusion characteristics of rigid-chain glassy polymers based on polyheteroarylenes (PHAs) have been studied in a wide interval of relative humidity and temperatures of thermal treatment of the polymer sorbents. Experimental data on water vapor sorption for polynaphthoyleneimidobenzimidazole (PNIB) and its copolymers with different chemical nature have been obtained. Water diffusion coefficients have been calculated, and parameters of their concentration and temperature dependences have been determined. It was found that water molecules sorbed by PNIB and its copolymers are strongly bounded. Water mobile and cluster states depend on the structure of macromolecules and thermal prehistory of polymer sorbents. It is shown that the translational coefficients of water diffusion for all PHAs are in the range from 10−9 to 10−8 cm2/s. The diffusion coefficients also increase slightly with temperature increasing, and their general dependence on temperature is satisfactorily described by the Arrhenius equation. The average activation energy of water diffusion varies from 24.3 to 25.9 kJ/mol. The hydrate numbers of rigid-chain PHAs functional groups have been determined. The above-mentioned results allow us to predict the sorption properties of heterocyclic macromolecular sorbents with complex chain architecture. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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21 pages, 3344 KiB  
Article
Defining the Collapse Point in Colloidal Unimolecular Polymer (CUP) Formation
by Ashish Zore, Peng Geng, Yuwei Zhang and Michael R. Van De Mark
Polymers 2022, 14(9), 1909; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14091909 - 07 May 2022
Cited by 1 | Viewed by 1702
Abstract
Colloidal unimolecular polymer (CUP) particles were made using polymers with different ratios of hydrophobic and hydrophilic monomers via a self-organization process known as water reduction. The water-reduction process and the collapse of the polymer chain to form a CUP were tracked using viscosity [...] Read more.
Colloidal unimolecular polymer (CUP) particles were made using polymers with different ratios of hydrophobic and hydrophilic monomers via a self-organization process known as water reduction. The water-reduction process and the collapse of the polymer chain to form a CUP were tracked using viscosity measurements as a function of composition. A vibration viscometer, which allowed for viscosity measurement as the water was being added during the water-reduction process, was utilized. The protocol was optimized and tested for factors such as temperature control, loss of material, measurement stability while stirring, and changes in the solution volume with the addition of water. The resulting viscosity curve provided the composition of Tetrahydrofuran (THF)/water mixture that triggers the collapse of a polymer chain into a particle. Hansen as well as dielectric parameters were related to the polymer composition and percentage v/v of THF/water mixture at the collapse point. It was observed that the collapse of the polymer chain occurred when the water/THF composition was at a water volume of between 53.8 to 59.3% in the solvent mixture. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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17 pages, 5879 KiB  
Article
Influence of Osmotic Pressure on Nanostructures in Thin Films of a Weakly-Segregated Block Copolymer and Its Blends with a Homopolymer
by Yi-Fang Chen, Jia-Wen Hong, Jung-Hong Chang, Belda Amelia Junisu and Ya-Sen Sun
Polymers 2021, 13(15), 2480; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13152480 - 28 Jul 2021
Cited by 8 | Viewed by 2475
Abstract
We studied the influence of osmotic pressure on nanostructures in thin films of a symmetric weakly-segregated polystyrene-block-poly (methyl methacrylate), P(S-b-MMA), block copolymer and its mixtures with a polystyrene (PS) homopolymer of various compositions. Thin films were deposited on substrates through surface neutralization. The [...] Read more.
We studied the influence of osmotic pressure on nanostructures in thin films of a symmetric weakly-segregated polystyrene-block-poly (methyl methacrylate), P(S-b-MMA), block copolymer and its mixtures with a polystyrene (PS) homopolymer of various compositions. Thin films were deposited on substrates through surface neutralization. The surface neutralization results from the PS mats, which were oxidized and cross-linked by UV-light exposure. Thus, thermal annealing produced perpendicularly oriented lamellae and perforated layers, depending on the content of added PS chains. Nevertheless, a mixed orientation was obtained from cylinders in thin films, where a high content of PS was blended with the P(S-b-MMA). A combination of UV-light exposure and acetic acid rinsing was used to remove the PMMA block. Interestingly, the treatment of PMMA removal inevitably produced osmotic pressure and consequently resulted in surface wrinkling of perpendicular lamellae. As a result, a hierarchical structure with two periodicities was obtained for wrinkled films with perpendicular lamellae. The formation of surface wrinkling is due to the interplay between UV-light exposure and acetic acid rinsing. UV-light exposure resulted in different mechanical properties between the skin and the inner region of a film. Acetic acid rinsing produced osmotic pressure. It was found that surface wrinkling could be suppressed by reducing film thickness, increasing PS content and using high-molecular-weight P(S-b-MMA) BCPs. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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17 pages, 3391 KiB  
Article
Phase Equilibrium and Interdiffusion in Blends of Polystyrene with Polyacrylates
by Uliana V. Nikulova and Anatoly E. Chalykh
Polymers 2021, 13(14), 2283; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13142283 - 12 Jul 2021
Cited by 2 | Viewed by 2229
Abstract
The solubility and interdiffusion of polystyrene (PS) with polymethyl acrylate (PMA), polyethyl acrylate (PEA), polybutyl acrylate (PBA), and polyethylhexyl acrylate (PEHA) have been studied by the optical interferometry method. Phase state diagrams are plotted. It is shown that they are characterized by the [...] Read more.
The solubility and interdiffusion of polystyrene (PS) with polymethyl acrylate (PMA), polyethyl acrylate (PEA), polybutyl acrylate (PBA), and polyethylhexyl acrylate (PEHA) have been studied by the optical interferometry method. Phase state diagrams are plotted. It is shown that they are characterized by the upper critical solution temperatures (UCST), which are localized in the temperature range above 450 K. Pair interaction parameters and their temperature dependences are determined and analyzed. Extrapolation of the temperature dependence of the interaction parameter was used to construct the dome of binodal curves and determine the spinodal curves in the framework of the Flory–Huggins theory. The diffusion coefficients of polystyrene into polyacrylates and polyacrylates into polystyrene are calculated. The dependences of the interdiffusion coefficients on the concentration, temperature, polystyrene molecular weight, and the number of carbons in the side chain of polyacrylate are analyzed. The numerical values of the interdiffusion coefficients of PS-1 into polyacrylates at 433 K change as −8.5 → −6.7 → −6.4 in the homologous series PMA → PEA → PBA. The coefficients of friction are calculated and the effect of change in the matrix structure on the diffusion of polystyrene in them is estimated. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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