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Polymers
Special Issues
Topology Effects on Polymer Properties
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Topology Effects on Polymer Properties

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

Deadline for manuscript submissions: closed (31 July 2020) | Viewed by 17627

Special Issue Editors

Prof. Dr. Fabio Ganazzoli

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Guest Editor
Department of Chemistry, Chemical, and Material Engineering “G. Natta”, Polytechnic University of Milan, Milan, Italy
Interests: polymer conformations and dynamics; branched polymers and dendrimers; molecular dynamics simulations; protein adsorption on biomaterials and nanomaterials; modeling of surface physisorption; modeling of molecular recognition
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Giuseppina Raffaini

E-Mail Website
Guest Editor
Department of Chemistry, Chemical, and Material Engineering “G. Natta”, Polytechnic University of Milan, Milan, Italy
Interests: molecular dynamics simulations; protein adsorption on biomaterials; modeling of nanomaterials and physisorption; host–guest complexes and molecular recognition; supramolecular complexes for drug delivery; chiral recognition and separation; adsorption and self-aggregation on DNA; organic corrosion inhibitors
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue aims to provide an overview of recent advances on the properties of polymers as a function of the macromolecular architecture and topology through both original research papers and reviews.

Recent synthetic methods have allowed preparing macromolecules with different topologies and very well-defined architectures, comprising ring polymers, star polymers, comb polymers, polymer brushes, and dendrimers, to name the most common ones. The further possibility of having unlikely repeat units, thus considering random and, in particular, block copolymers, can provide an additional degree of freedom to tailor the macromolecules’ properties and tune their performance. These different architectures may lead to new and peculiar polymer properties in that they can affect both the conformational and the dynamical properties of these polymers, hence, for instance, their rheological and transport properties. Additionally, the possible functionalization of the end groups in branched polymers may increase their versatility. Accordingly, all these features may lead to smart functional materials with a large array of possible applications in many, largely unrelated nanoscience and nanotechnology fields, in particular, for instance, in nanomedicine. We thus feel that a timely collection of original papers and reviews about these systems using a variety of techniques, from the theoretical and simulation studies to the experimental ones, would be of great interest in many fields of research.

Prof. Fabio Ganazzoli
Prof. Giuseppina Raffaini
Guest Editors

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. Polymers 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 2700 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

  • Star polymers
  • Comb polymers and polymer brushes
  • Dendrimers and cascade polymers
  • Ring polymers
  • Branched copolymers
  • Theory of polymer dynamics
  • Molecular simulations
  • Rheological and scattering methods
  • Applications of branched polymers

Published Papers (6 papers)

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Research

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12 pages, 3651 KiB  
Article
Bringing a New Flexible Mercaptoacetic Acid Linker to the Design of Coordination Polymers
by Agnieszka Ostasz and Alexander M. Kirillov
Polymers 2020, 12(6), 1329; https://doi.org/10.3390/polym12061329 - 10 Jun 2020
Cited by 1 | Viewed by 2671
Abstract
Two new 3D coordination polymers (CPs), formulated as [Zn(p-XBT)]n (1H) and [Cd(p-XBT)]n (2H), were assembled from a virtually unexplored p-xylylene-bis(2-mercaptoacetic) acid linker (p-XBTA) and characterized by infrared spectroscopy (FTIR), powder [...] Read more.
Two new 3D coordination polymers (CPs), formulated as [Zn(p-XBT)]n (1H) and [Cd(p-XBT)]n (2H), were assembled from a virtually unexplored p-xylylene-bis(2-mercaptoacetic) acid linker (p-XBTA) and characterized by infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), thermal analysis methods (TG-DSC, TG-FTIR), single-crystal X-ray diffraction, and topological analysis. Two different synthetic strategies were explored, namely the precipitation (P) and hydrothermal (H) methods, resulting in a Zn(II) derivative [Zn(p-XBT)·H2O]n (1P) and its dehydrated analogue [Zn(p-XBT)]n (1H), respectively. In the Cd(II)-containing system, the same [Cd(p-XBT)]n (2P = 2H) products were generated by both synthetic methods. Upon dehydration, 1P undergoes a “crystal-to-crystal” phase transition in the 170−185 °C temperature range, producing an anhydrous polycrystalline sample (1H). Both CPs 1H and 2H are isostructural and feature polymeric 3D metal-organic nets of the cds topological type, which are driven by the 4-linked metal and p-XBT2− nodes. These compounds represent unique examples of coordination polymers derived from p-xylylene-bis(2-mercaptoacetic) acid, thus opening up the use of this flexible S,O-heterodonor building block in the design of polymeric metal-organic architectures. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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20 pages, 4177 KiB  
Article
Nanolayers of Poly(N,N′-Dimethylaminoethyl Methacrylate) with a Star Topology and Their Antibacterial Activity
by Paulina Teper, Joanna Chojniak-Gronek, Anna Hercog, Natalia Oleszko-Torbus, Grażyna Płaza, Jerzy Kubacki, Katarzyna Balin, Agnieszka Kowalczuk and Barbara Mendrek
Polymers 2020, 12(1), 230; https://doi.org/10.3390/polym12010230 - 17 Jan 2020
Cited by 16 | Viewed by 3529
Abstract
In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The effect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N′-dimethylaminoethyl methacrylate) (PDMAEMA) [...] Read more.
In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The effect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N′-dimethylaminoethyl methacrylate) (PDMAEMA) to benzophenone functionalized glass or silicon supports was carried out via a “grafting to” approach using UV irradiation. To date, star polymer UV immobilization has never been used for this purpose. The thickness of the resulting nanolayers increased from 30 to 120 nm with the molar mass of the immobilized stars. The successful bonding of star PDMAEMA to the supports was confirmed by surface sensitive quantitative spectroscopic methods. Next, amino groups in the polymer layer were quaternized with bromoethane, and the influence of this modification on the antibacterial properties of the obtained materials was analyzed using a selected reference strain of bacteria. The resulting star nanolayer surfaces exhibited higher antimicrobial activity against Bacillus subtilis ATCC 6633 compared to that of the linear PDMAEMA analogues grafted onto a support. These promising results and the knowledge about the influence of the topology and modification of PDMAEMA layers on their properties may help in searching for new materials for antimicrobial applications in medicine. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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13 pages, 8955 KiB  
Article
Hydrolytic Degradation of Comb-Like Graft Poly (Lactide-co-Trimethylene Carbonate): The Role of Comonomer Compositions and Sequences
by Xuefei Leng, Wenwen Zhang, Yiying Wang, Yanshai Wang, Xiaoqing Li, Zhiyong Wei and Yang Li
Polymers 2019, 11(12), 2024; https://doi.org/10.3390/polym11122024 - 06 Dec 2019
Cited by 5 | Viewed by 2366
Abstract
The effect of sequence on copolymer properties is rarely studied, especially the degradation behavior of the biomaterials. A series of linear-comb block, gradient, random copolymers were successfully achieved using hydroxylated polybutadiene as the macroinitiator by simple ring-opening polymerization of l-lactide (l [...] Read more.
The effect of sequence on copolymer properties is rarely studied, especially the degradation behavior of the biomaterials. A series of linear-comb block, gradient, random copolymers were successfully achieved using hydroxylated polybutadiene as the macroinitiator by simple ring-opening polymerization of l-lactide (l-LA) and 1,3-trimethylene carbonate (TMC). The hydrolytic degradation behaviors of the copolymers were systemically evaluated by using nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM) to illustrate the influences of comonomer compositions and sequence structures. The linear-comb block copolymers (lcP(TMC-b-LLA)) with different compositions had different degradation rates, which increased with l-LA content. Thermal property changes were observed with decreased Tm and increased ΔHm in all block copolymers during the degradation. To combine different sequence structures, unique degradation behaviors were observed for the linear-comb block, gradient and random copolymers even with similar comonomer composition. The degradation rates of linear-comb PLLA-gradient-PTMC (lcP(LLA-grad-TMC)) and linear-comb PLLA-random-PTMC (lcP(LLA-ran-TMC)) were accelerated due to the loss of regularity and crystallinity, resulting in a remarkable decrease on weight retention and molar mass. The hydrolysis degradation rate increased in the order lcP(TMC-b-LLA), lcP(LLA-ran-TMC), lcP(LLA-grad-TMC). Therefore, the hydrolytic degradation behavior of comb-like graft copolymers depends on both the compositions and the sequences dramatically. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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Review

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32 pages, 6624 KiB  
Review
Local Effects of Ring Topology Observed in Polymer Conformation and Dynamics by Neutron Scattering—A Review
by Valeria Arrighi and Julia S. Higgins
Polymers 2020, 12(9), 1884; https://doi.org/10.3390/polym12091884 - 21 Aug 2020
Cited by 13 | Viewed by 3115
Abstract
The physical properties of polymers depend on a range of both structural and chemical parameters, and in particular, on molecular topology. Apparently simple changes such as joining chains at a point to form stars or simply joining the two ends to form a [...] Read more.
The physical properties of polymers depend on a range of both structural and chemical parameters, and in particular, on molecular topology. Apparently simple changes such as joining chains at a point to form stars or simply joining the two ends to form a ring can profoundly alter molecular conformation and dynamics, and hence properties. Cyclic polymers, as they do not have free ends, represent the simplest model system where reptation is completely suppressed. As a consequence, there exists a considerable literature and several reviews focused on high molecular weight cyclics where long range dynamics described by the reptation model comes into play. However, this is only one area of interest. Consideration of the conformation and dynamics of rings and chains, and of their mixtures, over molecular weights ranging from tens of repeat units up to and beyond the onset of entanglements and in both solution and melts has provided a rich literature for theory and simulation. Experimental work, particularly neutron scattering, has been limited by the difficulty of synthesizing well-characterized ring samples, and deuterated analogues. Here in the context of the broader literature we review investigations of local conformation and dynamics of linear and cyclic polymers, concentrating on poly(dimethyl siloxane) (PDMS) and covering a wide range of generally less high molar masses. Experimental data from small angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), including Neutron Spin Echo (NSE), are compared to theory and computational predictions. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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20 pages, 1022 KiB  
Review
Dendrimer Dynamics: A Review of Analytical Theories and Molecular Simulation Methods
by Fabio Ganazzoli and Giuseppina Raffaini
Polymers 2020, 12(6), 1387; https://doi.org/10.3390/polym12061387 - 20 Jun 2020
Cited by 11 | Viewed by 2288
Abstract
The theoretical study of dendrimers is reviewed, considering both analytical approaches and molecular simulation methods. We discuss the effect of molecular symmetry on the degeneracy of the relaxation times, and then the calculation of observable quantities, in particular the intrinsic viscosity, and then [...] Read more.
The theoretical study of dendrimers is reviewed, considering both analytical approaches and molecular simulation methods. We discuss the effect of molecular symmetry on the degeneracy of the relaxation times, and then the calculation of observable quantities, in particular the intrinsic viscosity, and then the viscoelastic complex modulus and the dynamic structure factor, in comparison with the available experimental data. In particular, the maximum intrinsic viscosity with increasing molar mass is analyzed in some detail. The approximations and/or assumptions of the adopted methods are also described in connection with analogous results for polymer of a different topology, in particular linear and star polymers. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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11 pages, 1820 KiB  
Review
Dendritic Macrosurfactant Assembly for Physical Functionalization of HIPE-Templated Polymers
by Chenhui Li, Shiqi Weng, Ming Jin and Decheng Wan
Polymers 2020, 12(4), 779; https://doi.org/10.3390/polym12040779 - 01 Apr 2020
Cited by 3 | Viewed by 2825
Abstract
High-internal-phase emulsion-templated macroporous polymers (polyHIPEs) have attracted much interest, but their surface functionalization remains a primary concern. Thus, competitive surface functionalization via physical self-assembly of macrosurfactants was reviewed. Dendritic and diblock-copolymer macrosurfactants were tested, and the former appeared to be more topologically competitive [...] Read more.
High-internal-phase emulsion-templated macroporous polymers (polyHIPEs) have attracted much interest, but their surface functionalization remains a primary concern. Thus, competitive surface functionalization via physical self-assembly of macrosurfactants was reviewed. Dendritic and diblock-copolymer macrosurfactants were tested, and the former appeared to be more topologically competitive in terms of solubility, viscosity, and versatility. In particular, hyperbranched polyethyleneimine (PEI) was transformed into dendritic PEI macrosurfactants through click-like N-alkylation with epoxy compounds. Free-standing PEI macrosurfactants were used as molecular nanocapsules for charge-selective guest encapsulation and robustly dictated the surface of a macroporous polymer through the HIPE technique, in which the macroporous polymer could act as a well-recoverable adsorbent. Metal nanoparticle-loaded PEI macrosurfactants could similarly lead to polyHIPE, whose surface was dictated by its catalytic component. Unlike conventional Pickering stabilizer, PEI macrosurfactant-based metal nanocomposite resulted in open-cellular polyHIPE, rendering the catalytic sites well accessible. The active amino groups on the polyHIPE could also be transformed into functional groups of aminopolycarboxylic acids, which could efficiently eliminate trace and heavy metal species in water. Full article
(This article belongs to the Special Issue Topology Effects on Polymer Properties)
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