Polymers

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4 pages, 200 KiB

Open AccessEditorial

Advances and Applications of Block Copolymers

by Nikolaos Politakos and Apostolos Avgeropoulos

Polymers 2023, 15(13), 2930; https://doi.org/10.3390/polym15132930 - 2 Jul 2023

Cited by 1 | Viewed by 3269

Abstract

Polymers are materials that have constantly evolved from the beginning of their discovery until the present day [...] Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

Research

Jump to: Editorial, Review

13 pages, 7831 KiB

Open AccessArticle

Nanostructuring Biobased Epoxy Resin with PEO-PPO-PEO Block Copolymer

by Irati Barandiaran, Joseba Gomez-Hermoso-de-Mendoza, Junkal Gutierrez, Agnieszka Tercjak and Galder Kortaberria

Polymers 2023, 15(5), 1216; https://doi.org/10.3390/polym15051216 - 28 Feb 2023

Cited by 4 | Viewed by 2360

Abstract

A biobased diglycidyl ether of vanillin (DGEVA) epoxy resin was nanostructured by poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-PPO-PEO) triblock copolymer. Due to the miscibility/immiscibility properties of the triblock copolymer in DGEVA resin, different morphologies were obtained depending on the triblock copolymer amount. A hexagonally [...] Read more.

A biobased diglycidyl ether of vanillin (DGEVA) epoxy resin was nanostructured by poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-PPO-PEO) triblock copolymer. Due to the miscibility/immiscibility properties of the triblock copolymer in DGEVA resin, different morphologies were obtained depending on the triblock copolymer amount. A hexagonally packed cylinder morphology was kept until reaching 30 wt% of PEO-PPO-PEO content, while a more complex three-phase morphology was obtained for 50 wt%, in which large worm-like PPO domains appear surrounded by two different phases, one of them rich in PEO and another phase rich in cured DGEVA. UV-vis measurements show that the transmittance is reduced with the increase in triblock copolymer content, especially at 50 wt%, probably due to the presence of PEO crystals detected by calorimetry. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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13 pages, 11038 KiB

Open AccessArticle

Thermal and Bulk Properties of Triblock Terpolymers and Modified Derivatives towards Novel Polymer Brushes

by Konstantinos Artopoiadis, Christina Miskaki, Gkreti-Maria Manesi, Ioannis Moutsios, Dimitrios Moschovas, Alexey A. Piryazev, Maria Karabela, Nikolaos E. Zafeiropoulos, Dimitri A. Ivanov and Apostolos Avgeropoulos

Polymers 2023, 15(4), 848; https://doi.org/10.3390/polym15040848 - 8 Feb 2023

Cited by 3 | Viewed by 2520

Abstract

We report the synthesis of three (3) linear triblock terpolymers, two (2) of the ABC type and one (1) of the BAC type, where A, B and C correspond to three chemically incompatible blocks such as polystyrene (PS), poly(butadiene) of exclusively (~100% vinyl-type) [...] Read more.

We report the synthesis of three (3) linear triblock terpolymers, two (2) of the ABC type and one (1) of the BAC type, where A, B and C correspond to three chemically incompatible blocks such as polystyrene (PS), poly(butadiene) of exclusively (~100% vinyl-type) -1,2 microstructure (PB_1,2) and poly(dimethylsiloxane) (PDMS) respectively. Living anionic polymerization enabled the synthesis of narrowly dispersed terpolymers with low average molecular weights and different composition ratios, as verified by multiple molecular characterization techniques. To evaluate their self-assembly behavior, transmission electron microscopy and small-angle X-ray scattering experiments were conducted, indicating the effect of asymmetric compositions and interactions as well as inversed segment sequence on the adopted morphologies. Furthermore, post-polymerization chemical modification reactions such as hydroboration and oxidation were carried out on the extremely low molecular weight PB_1,2 in all three terpolymer samples. To justify the successful incorporation of –OH groups in the polydiene segments and the preparation of polymeric brushes, various molecular, thermal, and surface analysis measurements were carried out. The synthesis and chemical modification reactions on such triblock terpolymers are performed for the first time to the best of our knowledge and constitute a promising route to design polymers for nanotechnology applications. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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26 pages, 2451 KiB

Open AccessArticle

Effect of Disparity in Self Dispersion Interactions on Phase Behaviors of Molten A-b-B Diblock Copolymers

by Xinyue Zhang, Mingge Zhao and Junhan Cho

Polymers 2023, 15(1), 30; https://doi.org/10.3390/polym15010030 - 21 Dec 2022

Cited by 2 | Viewed by 1549

Abstract

Phase behaviors of molten A-b-B diblock copolymers with disparity in self dispersion interactions are revisited here. A free energy functional is obtained for the corresponding Gaussian copolymers under the influence of effective interactions originating in the localized excess equation of state. The Landau [...] Read more.

Phase behaviors of molten A-b-B diblock copolymers with disparity in self dispersion interactions are revisited here. A free energy functional is obtained for the corresponding Gaussian copolymers under the influence of effective interactions originating in the localized excess equation of state. The Landau free energy expansion is then formulated as a series in powers of A and B density fluctuations up to 4th order. An alternative and equivalent Landau energy is also provided through the transformation of the order parameters to the fluctuations in block density difference and free volume fraction. The effective Flory χ is elicited from its quadratic term as the sum of the conventional enthalpic

χ_{H}

and the entropic

χ_{S}

that is related to energetic asymmetry mediated by copolymer bulk modulus. It is shown that the cubic term is balanced with Gaussian cubic vertex coefficients in corporation with energetics to yield a critical point at a composition rich in a component with stronger self interactions. The full phase diagrams with classical mesophases are given for the copolymers exhibiting ordering upon cooling and also for others revealing ordering reversely upon heating. These contrasting temperature responses, along with the skewness of phase boundaries, are discussed in relation to

χ_{H}

and

χ_{S}

. The pressure dependence of their ordering transitions is either barotropic or baroplastic; or anomalously exhibits anomalously both at different stages. These actions are all explained by the opposite responses of

χ_{H}

and

χ_{S}

to pressure. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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8 pages, 845 KiB

Open AccessCommunication

Small-Angle X-ray Scattering Analysis on the Estimation of Interaction Parameter of Poly(n-butyl acrylate)-b-poly(methyl methacrylate)

by Sang-In Lee, Min-Guk Seo, June Huh and Hyun-jong Paik

Polymers 2022, 14(24), 5567; https://doi.org/10.3390/polym14245567 - 19 Dec 2022

Cited by 3 | Viewed by 2288

Abstract

The temperature dependence of the Flory–Huggins interaction parameter

χ

for poly(n-butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) was quantified from small-angle X-ray scattering (SAXS) analysis using random phase approximation (RPA) theory. It was found from the

χ

estimation ( [...] Read more.

The temperature dependence of the Flory–Huggins interaction parameter

χ

for poly(n-butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) was quantified from small-angle X-ray scattering (SAXS) analysis using random phase approximation (RPA) theory. It was found from the

χ

estimation (

χ = 0.0103 + 14.76 / T

) that the enthalpic contribution,

χ_{H}

, a measure for temperature susceptibility of

χ

, is 1.7–4.5 folds smaller for PBA-b-PMMA than for the conventional styrene-diene-based block copolymers, which have been widely used for thermoplastic elastomers. This finding suggests that these fully acrylic components can be a desirable chemical pair for constituting terpolymers applied for thermally stable and mechanically resilient elastomers. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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12 pages, 2412 KiB

Open AccessArticle

Synthesis and Characterization of Hybrid Materials Derived from Conjugated Copolymers and Reduced Graphene Oxide

by Alexandros Ch. Lazanas, Athanasios Katsouras, Michael Spanos, Gkreti-Maria Manesi, Ioannis Moutsios, Dmitry V. Vashurkin, Dimitrios Moschovas, Christina Gioti, Michail A. Karakassides, Vasilis G. Gregoriou, Dimitri A. Ivanov, Christos L. Chochos and Apostolos Avgeropoulos

Polymers 2022, 14(23), 5292; https://doi.org/10.3390/polym14235292 - 3 Dec 2022

Cited by 5 | Viewed by 2187

Abstract

In this study the preparation of hybrid materials based on reduced graphene oxide (rGO) and conjugated copolymers is reported. By tuning the number and arrangement of thiophenes in the main chain (indacenothiophene or indacenothienothiophene) and the nature of the polymer acceptor (difluoro benzothiadiazole [...] Read more.

In this study the preparation of hybrid materials based on reduced graphene oxide (rGO) and conjugated copolymers is reported. By tuning the number and arrangement of thiophenes in the main chain (indacenothiophene or indacenothienothiophene) and the nature of the polymer acceptor (difluoro benzothiadiazole or diketopyrrolopyrrole) semiconducting copolymers were synthesized through Stille aromatic coupling and characterized to determine their molecular characteristics. The graphene oxide was synthesized using the Staudenmaier method and was further modified to reduced graphene oxide prior to structural characterization. Various mixtures with different rGO quantities and conjugated copolymers were prepared to determine the optoelectronic, thermal and morphological properties. An increase in the maximum absorbance ranging from 3 to 6 nm for all hybrid materials irrespective of the rGO concentration, when compared to the pristine conjugated copolymers, was estimated through the UV-Vis spectroscopy indicating a differentiation on the optical properties. Through voltammetric experiments the oxidation and reduction potentials were determined and the calculated HOMO and LUMO levels revealed a decrease on the electrochemical energy gap for low rGO concentrations. The study indicates the potential of the hybrid materials consisting of graphene oxide and high band gap conjugated copolymers for applications related to organic solar cells. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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19 pages, 28046 KiB

Open AccessArticle

Development of Double Hydrophilic Block Copolymer/Porphyrin Polyion Complex Micelles towards Photofunctional Nanoparticles

by Maria Karayianni, Dimitra Koufi and Stergios Pispas

Polymers 2022, 14(23), 5186; https://doi.org/10.3390/polym14235186 - 29 Nov 2022

Cited by 5 | Viewed by 1664

Abstract

The electrostatic complexation between double hydrophilic block copolymers (DHBCs) and a model porphyrin was explored as a means for the development of polyion complex micelles (PICs) that can be utilized as photosensitive porphyrin-loaded nanoparticles. Specifically, we employed a poly(2-(dimethylamino) ethyl methacrylate)-b-poly[(oligo [...] Read more.

The electrostatic complexation between double hydrophilic block copolymers (DHBCs) and a model porphyrin was explored as a means for the development of polyion complex micelles (PICs) that can be utilized as photosensitive porphyrin-loaded nanoparticles. Specifically, we employed a poly(2-(dimethylamino) ethyl methacrylate)-b-poly[(oligo ethylene glycol) methyl ether methacrylate] (PDMAEMA-b-POEGMA) diblock copolymer, along with its quaternized polyelectrolyte copolymer counterpart (QPDMAEMA-b-POEGMA) and 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p′,p″,p′′′-tetrasulfonic acid tetrasodium hydrate (TPPS) porphyrin. The (Q)PDMAEMA blocks enable electrostatic binding with TPPS, thus forming the micellar core, while the POEGMA blocks act as the corona of the micelles and impart solubility, biocompatibility, and stealth properties to the formed nanoparticles. Different mixing charge ratios were examined aiming to produce stable nanocarriers. The mass, size, size distribution and effective charge of the resulting nanoparticles, as well as their response to changes in their environment (i.e., pH and temperature) were investigated by dynamic and electrophoretic light scattering (DLS and ELS). Moreover, the photophysical properties of the complexed porphyrin along with further structural insight were obtained through UV-vis (200-800 nm) and fluorescence spectroscopy measurements. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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15 pages, 3286 KiB

Open AccessArticle

Polyacrylonitrile-b-Polystyrene Block Copolymer-Derived Hierarchical Porous Carbon Materials for Supercapacitor

by Ainhoa Álvarez-Gómez, Jiayin Yuan, Juan P. Fernández-Blázquez, Verónica San-Miguel and María B. Serrano

Polymers 2022, 14(23), 5109; https://doi.org/10.3390/polym14235109 - 24 Nov 2022

Cited by 7 | Viewed by 3261

Abstract

The use of block copolymers as a sacrificial template has been demonstrated to be a powerful method for obtaining porous carbons as electrode materials in energy storage devices. In this work, a block copolymer of polystyrene and polyacrylonitrile (PS−b−PAN) has been [...] Read more.

The use of block copolymers as a sacrificial template has been demonstrated to be a powerful method for obtaining porous carbons as electrode materials in energy storage devices. In this work, a block copolymer of polystyrene and polyacrylonitrile (PS−b−PAN) has been used as a precursor to produce fibers by electrospinning and powdered carbons, showing high carbon yield (~50%) due to a low sacrificial block content (f_PS ≈ 0.16). Both materials have been compared structurally (in addition to comparing their electrochemical behavior). The porous carbon fibers showed superior pore formation capability and exhibited a hierarchical porous structure, with small and large mesopores and a relatively high surface area (~492 m²/g) with a considerable quantity of O/N surface content, which translates into outstanding electrochemical performance with excellent cycle stability (close to 100% capacitance retention after 10,000 cycles) and high capacitance value (254 F/g measured at 1 A/g). Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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14 pages, 3443 KiB

Open AccessArticle

Graft Polymerization of Acrylamide in an Aqueous Dispersion of Collagen in the Presence of Tributylborane

by Yulia L. Kuznetsova, Karina S. Sustaeva, Alexander V. Mitin, Evgeniy A. Zakharychev, Marfa N. Egorikhina, Victoria O. Chasova, Ekaterina A. Farafontova, Irina I. Kobyakova and Lyudmila L. Semenycheva

Polymers 2022, 14(22), 4900; https://doi.org/10.3390/polym14224900 - 13 Nov 2022

Cited by 6 | Viewed by 2176

Abstract

Graft copolymers of collagen and polyacrylamide (PAA) were synthesized in a suspension of acetic acid dispersion of fish collagen and acrylamide (AA) in the presence of tributylborane (TBB). The characteristics of the copolymers were determined using infrared spectroscopy and gel permeation chromatography (GPC). [...] Read more.

Graft copolymers of collagen and polyacrylamide (PAA) were synthesized in a suspension of acetic acid dispersion of fish collagen and acrylamide (AA) in the presence of tributylborane (TBB). The characteristics of the copolymers were determined using infrared spectroscopy and gel permeation chromatography (GPC). Differences in synthesis temperature between 25 and 60 °C had no significant effect on either proportion of graft polyacrylamide generated or its molecular weight. However, photomicrographs taken with the aid of a scanning electron microscope showed a breakdown of the fibrillar structure of the collagen within the copolymer at synthesis temperatures greater than 25 °C. The mechanical properties of the films and the cytotoxicity of the obtained copolymer samples were studied. The sample of a hybrid copolymer of collagen and PAA obtained at 60 °C has stronger mechanical properties compared to other tested samples. Its low cytotoxicity, when the monomer is removed, makes materials based on it promising in scaffold technologies. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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20 pages, 6424 KiB

Open AccessArticle

Crystallization Behavior of Isotactic Propene-Octene Random Copolymers

by Miriam Scoti, Fabio De Stefano, Angelo Giordano, Giovanni Talarico and Claudio De Rosa

Polymers 2022, 14(19), 4032; https://doi.org/10.3390/polym14194032 - 26 Sep 2022

Cited by 11 | Viewed by 1934

Abstract

The crystallization behavior of random propene-octene isotactic copolymers (iPPC8) prepared with a homogeneous metallocene catalyst has been studied. Samples of iPPC8 with low octene content up to about 7 mol% were isothermally crystallized from the melt at various crystallization temperatures. The samples crystallize [...] Read more.

The crystallization behavior of random propene-octene isotactic copolymers (iPPC8) prepared with a homogeneous metallocene catalyst has been studied. Samples of iPPC8 with low octene content up to about 7 mol% were isothermally crystallized from the melt at various crystallization temperatures. The samples crystallize in mixtures of the α and γ forms of isotactic polypropylene (iPP). The relative amount of γ form increases with increasing crystallization temperature, and a maximum amount of γ form (f_γ(max)) is achieved for each sample. The crystallization behavior of iPPC8 copolymers is compared with the crystallization from the melt of propene–ethylene, propene–butene, propene–pentene, and propene–hexene copolymers. The results show that the behavior of iPPC8 copolymers is completely different from those described in the literature for the other copolymers of iPP. In fact, the maximum amount of γ form achieved in samples of different copolymers of iPP generally increases with increasing comonomer content, while in iPPC8 copolymers the maximum amount of γ form decreases with increasing octene content. The different behaviors are discussed based on the inclusion of co-monomeric units in the crystals of α and γ forms of iPP or their exclusion from the crystals. In iPPC8 copolymers, octene units are excluded from the crystals giving only the interruption effect that shortens the length of regular propene sequences, inducing crystallization of the γ form at low octene concentrations, lower than 2 mol%. At higher octene concentration, the crystallization of the kinetically favored α form prevails. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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16 pages, 2609 KiB

Open AccessArticle

Melt-Crystallizations of α and γ Forms of Isotactic Polypropylene in Propene-Butene Copolymers

by Miriam Scoti, Fabio De Stefano, Filomena Piscitelli, Giovanni Talarico, Angelo Giordano and Claudio De Rosa

Polymers 2022, 14(18), 3873; https://doi.org/10.3390/polym14183873 - 16 Sep 2022

Cited by 10 | Viewed by 1977

Abstract

Random isotactic propene-butene copolymers (iPPC4) of different stereoregularity have been synthesized with three different homogeneous single center metallocene catalysts having different stereoselectivity. All samples crystallize from the polymerization solution in mixtures of α and γ forms, and the relative amount of γ form [...] Read more.

Random isotactic propene-butene copolymers (iPPC4) of different stereoregularity have been synthesized with three different homogeneous single center metallocene catalysts having different stereoselectivity. All samples crystallize from the polymerization solution in mixtures of α and γ forms, and the relative amount of γ form increases with increasing concentrations of butene and of rr stereodefects. All samples crystallize from the melt in mixtures of α and γ forms and the fraction of γ form increases with decreasing cooling rate. At high cooling rates, the crystallization of the α form is always favored, even for samples that contain high total concentration of defects that should crystallize in the γ form. The results demonstrate that in iPPs containing significant concentrations of defects, such as stereodefects and comonomeric units, the γ form is the thermodynamically stable form of iPP and crystallizes in selective conditions of very slow crystallization, whereas the α form is the kinetically favored form and crystallizes in conditions of fast crystallization. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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13 pages, 13431 KiB

Open AccessArticle

The Effect of Topology on Block Copolymer Nanoparticles: Linear versus Star Block Copolymers in Toluene

by Yuan Zhang, Peng Wang, Nan Li, Chunyan Guo and Sumin Li

Polymers 2022, 14(17), 3691; https://doi.org/10.3390/polym14173691 - 5 Sep 2022

Cited by 6 | Viewed by 2177

Abstract

Linear and star block copolymer (BCP) nanoparticles of (polystyrene-block-poly(4-vinylpyridine))_n (PS-b-P4VP)_n with arm numbers of 1, 2, 3, and 4 were prepared by two methods of polymerization-induced self-assembly (PISA) and general self-assembly of block copolymers in the low-polar [...] Read more.

Linear and star block copolymer (BCP) nanoparticles of (polystyrene-block-poly(4-vinylpyridine))_n (PS-b-P4VP)_n with arm numbers of 1, 2, 3, and 4 were prepared by two methods of polymerization-induced self-assembly (PISA) and general self-assembly of block copolymers in the low-polar organic solvent, toluene. The effect of the arm number on the size and/or morphology of the (PS-b-P4VP)_n nanoassemblies synthesized by the two methods in toluene and on the polymerization kinetics was investigated in detail. Our results show that in toluene, a low-polar solvent, the topology not only affected the morphology of the BCP nanoparticles prepared by PISA, but also influenced the BCP nanoparticles synthesized through general self-assembly. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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16 pages, 5349 KiB

Open AccessArticle

Simultaneous Removal of Cr(VI) and Phenol from Water Using Silica-di-Block Polymer Hybrids: Adsorption Kinetics and Thermodynamics

by Jia Qu, Qiang Yang, Wei Gong, Meilan Li and Baoyue Cao

Polymers 2022, 14(14), 2894; https://doi.org/10.3390/polym14142894 - 16 Jul 2022

Cited by 10 | Viewed by 1826

Abstract

Heavy metal ions and organic pollutants often coexist in industrial effluents. In this work, silica-di-block polymer hybrids (SiO₂-g-PBA-b-PDMAEMA) with two ratios (SiO₂/BA/DMAEMA = 1/50/250 and 1/60/240) were designed and prepared for the simultaneous removal of Cr(VI) and phenol via [...] Read more.

Heavy metal ions and organic pollutants often coexist in industrial effluents. In this work, silica-di-block polymer hybrids (SiO₂-g-PBA-b-PDMAEMA) with two ratios (SiO₂/BA/DMAEMA = 1/50/250 and 1/60/240) were designed and prepared for the simultaneous removal of Cr(VI) and phenol via a surface-initiated atom-transfer radical polymerization process using butyl methacrylate (BA) as a hydrophobic monomer and 2-(Dimethylamino)ethylmethacrylate (DMAEMA) as a hydrophilic monomer. The removal efficiency of Cr(VI) and phenol by the hybrids reached 88.25% and 88.17%, respectively. The sample with a larger proportion of hydrophilic PDMAEMA showed better adsorption of Cr(VI), and the sample with a larger proportion of hydrophobic PBA showed better adsorption of phenol. In binary systems, the presence of Cr(VI) inhibited the adsorption of phenol, yet the presence of phenol had a negligible effect on the adsorption of Cr(VI). Kinetics studies showed that the adsorption of Cr(VI) and phenol fitted the pseudo-second-order model well. Thermodynamic studies showed that the adsorption behavior of Cr(VI) and phenol were better described by the Langmuir adsorption isotherm equation, and the adsorption of Cr(VI) and phenol were all spontaneous adsorptions driven by enthalpy. The adsorbent still possessed good adsorption capacity for Cr(VI) and phenol after six adsorption–desorption cycles. These findings show that SiO₂-g-PBA-b-PDMAEMA hybrids represent a satisfying adsorption material for the simultaneous removal of heavy metal ions and organic pollutants. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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13 pages, 2698 KiB

Open AccessEditor’s ChoiceArticle

Synthesis and Thermal Analysis of Non-Covalent PS-b-SC-b-P2VP Triblock Terpolymers via Polylactide Stereocomplexation

by Ameen Arkanji, Viko Ladelta, Konstantinos Ntetsikas and Nikos Hadjichristidis

Polymers 2022, 14(12), 2431; https://doi.org/10.3390/polym14122431 - 15 Jun 2022

Cited by 6 | Viewed by 2352

Abstract

Polylactides (PLAs) are thermoplastic materials known for their wide range of applications. Moreover, the equimolar mixtures of poly(L-Lactide) (PLLA) and poly(D-Lactide) (PDLA) can form stereocomplexes (SCs), which leads to the formation of new non-covalent complex macromolecular architectures. In this work, we report the [...] Read more.

Polylactides (PLAs) are thermoplastic materials known for their wide range of applications. Moreover, the equimolar mixtures of poly(L-Lactide) (PLLA) and poly(D-Lactide) (PDLA) can form stereocomplexes (SCs), which leads to the formation of new non-covalent complex macromolecular architectures. In this work, we report the synthesis and characterization of non-covalent triblock terpolymers of polystyrene-b-stereocomplex PLA-b-poly(2-vinylpyridine) (PS-b-SC-b-P2VP). Well-defined ω-hydroxy-PS and P2VP were synthesized by “living” anionic polymerization high-vacuum techniques with sec-BuLi as initiator, followed by termination with ethylene oxide. The resulting PS-OH and P2VP-OH were used as macroinitiators for the ring-opening polymerization (ROP) of DLA and LLA with Sn(Oct)₂ as a catalyst to afford PS-b-PDLA and P2VP-b-PLLA, respectively. SC formation was achieved by mixing PS-b-PDLA and P2VP-b-PLLA chloroform solutions containing equimolar PLAs segments, followed by precipitation into n-hexane. The molecular characteristics of the resulting block copolymers (BCPs) were determined by ¹H NMR, size exclusion chromatography, and Fourier-transform infrared spectroscopy. The formation of PS-b-SC-b-P2VP and the effect of molecular weight variation of PLA blocks on the resulting polymers, were investigated by differential scanning calorimetry, X-ray powder diffraction, and circular dichroism spectroscopies. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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12 pages, 2183 KiB

Open AccessArticle

Block Copolymer Modified Nanonetwork Epoxy Resin for Superior Energy Dissipation

by Suhail K. Siddique, Hassan Sadek, Tsung-Lun Lee, Cheng-Yuan Tsai, Shou-Yi Chang, Hsin-Hsien Tsai, Te-Shun Lin, Gkreti-Maria Manesi, Apostolos Avgeropoulos and Rong-Ming Ho

Polymers 2022, 14(9), 1891; https://doi.org/10.3390/polym14091891 - 5 May 2022

Cited by 3 | Viewed by 2738

Abstract

Herein, this work aims to fabricate well-ordered nanonetwork epoxy resin modified with poly(butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) block copolymer (BCP) for enhanced energy dissipation using a self-assembled diblock copolymer of polystyrene-b-poly(dimethylsiloxane) (PS-b-PDMS) with gyroid and diamond [...] Read more.

Herein, this work aims to fabricate well-ordered nanonetwork epoxy resin modified with poly(butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) block copolymer (BCP) for enhanced energy dissipation using a self-assembled diblock copolymer of polystyrene-b-poly(dimethylsiloxane) (PS-b-PDMS) with gyroid and diamond structures as templates. A systematic study of mechanical properties using nanoindentation of epoxy resin with gyroid- and diamond-structures after modification revealed significant enhancement in energy dissipation, with the values of 0.36 ± 0.02 nJ (gyroid) and 0.43 ± 0.03 nJ (diamond), respectively, when compared to intrinsic epoxy resin (approximately 0.02 ± 0.002 nJ) with brittle characteristics. This enhanced property is attributed to the synergic effect of the deliberate structure with well-ordered nanonetwork texture and the toughening of BCP-based modifiers at the molecular level. In addition to the deliberate structural effect from the nanonetwork texture, the BCP modifier composed of epoxy-philic hard segment and epoxy-phobic soft segment led to dispersed soft-segment domains in the nanonetwork-structured epoxy matrix with superior interfacial strength for the enhancement of applied energy dissipation. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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17 pages, 3431 KiB

Open AccessEditor’s ChoiceArticle

Poly(vinyl pyridine) and Its Quaternized Derivatives: Understanding Their Solvation and Solid State Properties

by Katerina Mavronasou, Alexandra Zamboulis, Panagiotis Klonos, Apostolos Kyritsis, Dimitrios N. Bikiaris, Raffaello Papadakis and Ioanna Deligkiozi

Polymers 2022, 14(4), 804; https://doi.org/10.3390/polym14040804 - 19 Feb 2022

Cited by 26 | Viewed by 9592

Abstract

A series of N-methyl quaternized derivatives of poly(4-vinylpyridine) (PVP) were synthesized in high yields with different degrees of quaternization, obtained by varying the methyl iodide molar ratio and affording products with unexplored optical and solvation properties. The impact of quaternization on the physicochemical [...] Read more.

A series of N-methyl quaternized derivatives of poly(4-vinylpyridine) (PVP) were synthesized in high yields with different degrees of quaternization, obtained by varying the methyl iodide molar ratio and affording products with unexplored optical and solvation properties. The impact of quaternization on the physicochemical properties of the copolymers, and notably the solvation properties, was further studied. The structure of the synthesized polymers and the quaternization degrees were determined by infrared and nuclear magnetic spectroscopies, while their thermal characteristics were studied by differential scanning calorimetry and their thermal stability and degradation by thermogravimetric analysis (TG-DTA). Attention was given to their optical properties, where UV-Vis and diffuse reflectance spectroscopy (DRS) measurements were carried out. The optical band gap of the polymers was calculated and correlated with the degree of quaternization. The study was further orientated towards the solvation properties of the polymers in binary solvent mixtures that strongly depend on the degree of quaternization, enabling a better understanding of the key polymer (solute)-solvent interactions. The assessment of the underlying solvation phenomena was performed in a system of different ratios of DMSO/H₂O and the solvatochromic indicator used was Reichardt’s dye. Solvent polarity parameters have a significant effect on the visible spectra of the nitrogen quaternization of PVP studied in this work and a detailed path towards this assessment is presented. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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Review

Jump to: Editorial, Research

31 pages, 7838 KiB

Open AccessReview

Block Copolymers in 3D/4D Printing: Advances and Applications as Biomaterials

by Nikolaos Politakos

Polymers 2023, 15(2), 322; https://doi.org/10.3390/polym15020322 - 8 Jan 2023

Cited by 11 | Viewed by 3981

Abstract

3D printing is a manufacturing technique in constant evolution. Day by day, new materials and methods are discovered, making 3D printing continually develop. 3D printers are also evolving, giving us objects with better resolution, faster, and in mass production. One of the areas [...] Read more.

3D printing is a manufacturing technique in constant evolution. Day by day, new materials and methods are discovered, making 3D printing continually develop. 3D printers are also evolving, giving us objects with better resolution, faster, and in mass production. One of the areas in 3D printing that has excellent potential is 4D printing. It is a technique involving materials that can react to an environmental stimulus (pH, heat, magnetism, humidity, electricity, and light), causing an alteration in their physical or chemical state and performing another function. Lately, 3D/4D printing has been increasingly used for fabricating materials aiming at drug delivery, scaffolds, bioinks, tissue engineering (soft and hard), synthetic organs, and even printed cells. The majority of the materials used in 3D printing are polymeric. These materials can be of natural origin or synthetic ones of different architectures and combinations. The use of block copolymers can combine the exemplary properties of both blocks to have better mechanics, processability, biocompatibility, and possible stimulus behavior via tunable structures. This review has gathered fundamental aspects of 3D/4D printing for biomaterials, and it shows the advances and applications of block copolymers in the field of biomaterials over the last years. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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31 pages, 5617 KiB

Open AccessReview

Well-Defined Nanostructures by Block Copolymers and Mass Transport Applications in Energy Conversion

by Shuhui Ma, Yushuang Hou, Jinlin Hao, Cuncai Lin, Jiawei Zhao and Xin Sui

Polymers 2022, 14(21), 4568; https://doi.org/10.3390/polym14214568 - 28 Oct 2022

Cited by 7 | Viewed by 3904

Abstract

With the speedy progress in the research of nanomaterials, self-assembly technology has captured the high-profile interest of researchers because of its simplicity and ease of spontaneous formation of a stable ordered aggregation system. The self-assembly of block copolymers can be precisely regulated at [...] Read more.

With the speedy progress in the research of nanomaterials, self-assembly technology has captured the high-profile interest of researchers because of its simplicity and ease of spontaneous formation of a stable ordered aggregation system. The self-assembly of block copolymers can be precisely regulated at the nanoscale to overcome the physical limits of conventional processing techniques. This bottom-up assembly strategy is simple, easy to control, and associated with high density and high order, which is of great significance for mass transportation through membrane materials. In this review, to investigate the regulation of block copolymer self-assembly structures, we systematically explored the factors that affect the self-assembly nanostructure. After discussing the formation of nanostructures of diverse block copolymers, this review highlights block copolymer-based mass transport membranes, which play the role of “energy enhancers” in concentration cells, fuel cells, and rechargeable batteries. We firmly believe that the introduction of block copolymers can facilitate the novel energy conversion to an entirely new plateau, and the research can inform a new generation of block copolymers for more promotion and improvement in new energy applications. Full article

(This article belongs to the Special Issue Advances and Applications of Block Copolymers)

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