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Emerging Topics in Life Sciences Dec 2022Biology demonstrates meticulous ways to control biomaterials self-assemble into ordered and disordered structures to carry out necessary bioprocesses. Empowering the... (Review)
Review
Biology demonstrates meticulous ways to control biomaterials self-assemble into ordered and disordered structures to carry out necessary bioprocesses. Empowering the synthetic polymers to self-assemble like biomaterials is a hallmark of polymer physics studies. Unlike protein engineering, polymer science demystifies self-assembly by purposely embedding particular functional groups into the backbone of the polymer while isolating others. The polymer field has now entered an era of advancing materials design by mimicking nature to a very large extend. For example, we can make sequence-specific polymers to study highly ordered mesostructures similar to studying proteins, and use charged polymers to study liquid-liquid phase separation as in membraneless organelles. This mini-review summarizes recent advances in studying self-assembly using bio-inspired strategies on single-component and multi-component systems. Sequence-defined techniques are used to make on-demand hybrid materials to isolate the effects of chirality and chemistry in synthetic block copolymer self-assembly. In the meantime, sequence patterning leads to more hierarchical assemblies comprised of only hydrophobic and hydrophilic comonomers. The second half of the review discusses complex coacervates formed as a result of the associative charge interactions of oppositely charged polyelectrolytes. The tunable phase behavior and viscoelasticity are unique in studying liquid macrophase separation because the slow polymer relaxation comes primarily from charge interactions. Studies of bio-inspired polymer self-assembly significantly impact how we optimize user-defined materials on a molecular level.
Topics: Polymers; Proteins; Polyelectrolytes; Hydrophobic and Hydrophilic Interactions; Biocompatible Materials
PubMed: 36254846
DOI: 10.1042/ETLS20220057 -
Acta Biomaterialia Apr 2021Hydrogels are an attractive class of materials that possess similar structural and functional characteristics to wet biological tissues and demonstrate a diversity of... (Review)
Review
Hydrogels are an attractive class of materials that possess similar structural and functional characteristics to wet biological tissues and demonstrate a diversity of applications in biomedical engineering. Silk fibroin (SF) is a unique natural polymer due to its fibrous protein nature, versatile formats, biocompatibility, tunable biodegradation and is thus a good hydrogel candidate for bio-applications. Compared to synthetic polymer hydrogels, poor mechanical performance is still a fatal drawback that hinders the application of SF hydrogels as structural materials. Researchers have attempted to develop strategies to construct silk fibroin-based high-strength hydrogels (SF-HSHs). Herein, we firstly provide an overview of the approaches of processing SF-HSHs with a focus on the physical/non-covalent crosslinking mechanisms. The examples of SF-HSHs are discussed in detail under four categories, including physical-crosslinked, dual-crosslinked, double network and composite hydrogels respectively. A brief section follows to elucidate on the gelation mechanisms of SF-HSHs before a description of the utility of SF-HSHs in biomedicine and devices is presented. Finally, the potential challenges and future development of SF-HSHs are briefly discussed. This review aims to enhance our understanding of the structure-mechanical property-function relationships of soft materials made from natural polymers and guide future research of silk fibroin-based hydrogels for biomedical applications. STATEMENT OF SIGNIFICANCE: Silk fibroin (SF) extracted from silk fibres is increasingly applied in the biomedical field, and SF hydrogel has been an emerging area for frontier bio-research. Since SF biopolymer has an intrinsic tendency to form regular β-sheet stacks, it can be processed into purely physically crosslinked hydrogels, thus avoiding the use of chemical crosslinkers. Nevertheless, akin to other natural polymers, lab-produced SF is variable (i.e. the molecular weight and distribution), and the gelation of SF hydrogel is challenging to control. In addition, hydrogels made from SF are usually weak and brittle, which hinders the wide use of this biofriendly and biodegradable hydrogel. Recently, there is a pressing need for high strength hydrogels from natural polymers for biomedical applications, and SF is proposed as a strong candidate. Therefore, we have studied the literature in the past 10 years and would like to focus on the gelation mechanism and mechanical strength of SF hydrogels for the review.
Topics: Fibroins; Hydrogels; Polymers; Silk
PubMed: 33601067
DOI: 10.1016/j.actbio.2021.02.018 -
Molecules (Basel, Switzerland) Sep 2022A new programed upper critical solution temperature-type thermoresponsive polymer was developed using water-soluble anionic polymer conjugates derived from...
A new programed upper critical solution temperature-type thermoresponsive polymer was developed using water-soluble anionic polymer conjugates derived from polyallylamine and phthalic acid with cleavage-induced phase transition property. Intrinsic charge inversion from anion to cation of the polymer side chain is induced through a side chain cleavage reaction in acidic aqueous media. With the progress of side chain cleavage under fixed external conditions, the polymer conjugates express a thermoresponsive property, followed by shifting a phase boundary due to the change in polymer composition. When the phase transition boundary eventually reached the examined temperature, phase transition occurs under fixed external conditions. Such new insight obtained in this study opens up the new concept of time-programed stimuli-responsive polymer possessing a cleavage-induced phase transition.
Topics: Anions; Phase Transition; Polymers; Stimuli Responsive Polymers; Temperature; Water
PubMed: 36144815
DOI: 10.3390/molecules27186082 -
Sensors (Basel, Switzerland) Nov 2021We designed simply fabricated, highly sensitive, and cost-effective dual-polymer-coated Fabry-Perot interferometer (DFPI)-based temperature sensors by employing...
We designed simply fabricated, highly sensitive, and cost-effective dual-polymer-coated Fabry-Perot interferometer (DFPI)-based temperature sensors by employing thermosensitive polymers and non-thermosensitive polymers, as well as different two successive dip-coating techniques (stepwise dip coating and polymer mixture coating). Seven sensors were fabricated using different polymer combinations for performance optimization. The experiments demonstrated that the stepwise dip-coated dual thermosensitive polymer sensors exhibited the highest sensitivity (2142.5 pm °C for poly(methyl methacrylate)-polycarbonate (PMMA_PC) and 785.5 pm °C for poly(methyl methacrylate)- polystyrene (PMMA_PS)). Conversely, the polymer-mixture-coated sensors yielded low sensitivities (339.5 pm °C for the poly(methyl methacrylate)-polycarbonate mixture (PMMA_PC mixture) and 233.5 pm °C for the poly(methyl methacrylate)-polystyrene mixture (PMMA_PS mixture). Thus, the coating method, polymer selection, and thin air-bubble-free coating are crucial for high-sensitivity DFPI-based sensors. Furthermore, the DFPI-based sensors yielded stable readouts, based on three measurements. Our comprehensive results confirm the effectiveness, reproducibility, stability, fast response, feasibility, and accuracy of temperature measurements using the proposed sensors. The excellent performance and simplicity of our proposed sensors are promising for biomedical, biochemical, and physical applications.
Topics: Polymers; Polymethyl Methacrylate; Polystyrenes; Reproducibility of Results; Temperature
PubMed: 34833708
DOI: 10.3390/s21227632 -
ChemPlusChem May 2022The chiral self-assembly of polymers in dispersions plays an important role in chiral chemistry and self-assembly. In general, both polymerization-induced self-assembly... (Review)
Review
The chiral self-assembly of polymers in dispersions plays an important role in chiral chemistry and self-assembly. In general, both polymerization-induced self-assembly (PISA) and post-polymerization self-assembly can be used to prepare polymer nanoassemblies. In chirality induction or transfer processes, the self-assembly manner of the polymers greatly affects the chiral expression of the nanostructure and cannot be ignored in the chiral fields. Moreover, unique chiral expression and morphological transition of polymer assemblies in dispersions enable the preparation of advanced functional chiroptical materials. Herein, this Review discusses recent advances in chiral expression and morphology control in polymer dispersion systems, particularly the comparison between traditional post-polymerization self-assembly and in situ PISA strategies, to predict and advance chirality control in polymers.
Topics: Nanostructures; Polymerization; Polymers
PubMed: 35182052
DOI: 10.1002/cplu.202100556 -
Macromolecular Rapid Communications Mar 2024Entropy is a universal concept across the physics of mixtures. While the role of entropy in other multicomponent materials has been appreciated, its effects in polymers...
Entropy is a universal concept across the physics of mixtures. While the role of entropy in other multicomponent materials has been appreciated, its effects in polymers and plastics have not. In this work, it is demonstrated that the seemingly small mixing entropy contributes to the miscibility and performance of polymer alloys. Experimental and modeling studies on over 30 polymer pairs reveal a strong correlation between entropy, morphology, and mechanical properties, while elucidating the mechanism behind: in polymer blends with weak interactions, entropy leads to homogeneously dispersed nanosized domains stabilized by highly entangled chains. This unique microstructure promotes uniform plastic deformation at the interface, thus improving the toughness of conventional brittle polymers by 1-2 orders of magnitude without sacrificing other properties, analogous to high-entropy metallic alloys. The proposed strategy also applies to ternary polymer systems and copolymers, offering a new pathway toward the development of sustainable polymers.
Topics: Entropy; Polymers; Alloys; Plastics
PubMed: 38102953
DOI: 10.1002/marc.202300543 -
Molecules (Basel, Switzerland) Sep 2022The interaction of water with polymers is an intensively studied topic. Vibrational spectroscopy techniques, mid-infrared (MIR) and Raman, were often used to investigate...
The interaction of water with polymers is an intensively studied topic. Vibrational spectroscopy techniques, mid-infrared (MIR) and Raman, were often used to investigate the properties of water-polymer systems. On the other hand, relatively little attention has been given to the potential of using near-infrared (NIR) spectroscopy (12,500-4000 cm; 800-2500 nm) for exploring this problem. NIR spectroscopy delivers exclusive opportunities for the investigation of molecular structure and interactions. This technique derives information from overtones and combination bands, which provide unique insights into molecular interactions. It is also very well suited for the investigation of aqueous systems, as both the bands of water and the polymer can be reliably acquired in a range of concentrations in a more straightforward manner than it is possible with MIR spectroscopy. In this study, we applied NIR spectroscopy to investigate interactions of water with polymers of varying hydrophobicity: polytetrafluoroethylene (PTFE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), polyoxymethylene (POM), polyamide 6 (PA), lignin (Lig), chitin (Chi) and cellulose (Cell). Polymer-water mixtures in the concentration range of water between 1-10%(/) were investigated. Spectra analysis and interpretation were performed with the use of difference spectroscopy, Principal Component Analysis (PCA), Median Linkage Clustering (MLC), Partial Least Squares Regression (PLSR), Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) and Two-Dimensional Correlation Spectroscopy (2D-COS). Additionally, from the obtained data, aquagrams were constructed and interpreted with aid of the conclusions drawn from the conventional approaches. We deepened insights into the problem of water bands obscuring compound-specific signals in the NIR spectrum, which is often a limiting factor in analytical applications. The study unveiled clearly visible trends in NIR spectra associated with the chemical nature of the polymer and its increasing hydrophilicity. We demonstrated that changes in the NIR spectrum of water are manifested even in the case of interaction with highly hydrophobic polymers (e.g., PTFE). Furthermore, the unveiled spectral patterns of water in the presence of different polymers were found to be dissimilar between the two major water bands in NIR spectrum ( + and + ).
Topics: Cellulose; Chitin; Lignin; Polymers; Polypropylenes; Polystyrenes; Polytetrafluoroethylene; Polyvinyl Chloride; Spectroscopy, Near-Infrared; Water
PubMed: 36144616
DOI: 10.3390/molecules27185882 -
Nature Communications Jan 2023Polymers with low ceiling temperatures (T) are highly desirable as they can depolymerize under mild conditions, but they typically suffer from demanding synthetic...
Polymers with low ceiling temperatures (T) are highly desirable as they can depolymerize under mild conditions, but they typically suffer from demanding synthetic conditions and poor stability. We envision that this challenge can be addressed by developing high-T polymers that can be converted into low-T polymers on demand. Here, we demonstrate the mechanochemical generation of a low-T polymer, poly(2,5-dihydrofuran) (PDHF), from an unsaturated polyether that contains cyclobutane-fused THF in each repeat unit. Upon mechanically induced cycloreversion of cyclobutane, each repeat unit generates three repeat units of PDHF. The resulting PDHF completely depolymerizes into 2,5-dihydrofuran in the presence of a ruthenium catalyst. The mechanochemical generation of the otherwise difficult-to-synthesize PDHF highlights the power of polymer mechanochemistry in accessing elusive structures. The concept of mechanochemically regulating the T of polymers can be applied to develop next-generation sustainable plastics.
Topics: Polymers; Cyclobutanes; Plastics; Catalysis
PubMed: 36641481
DOI: 10.1038/s41467-023-35925-2 -
ACS Applied Materials & Interfaces May 2020Biocidal compounds that quickly kill bacterial cells and are then deactivated in the surrounding without causing environmental problems are of great current interest....
Biocidal compounds that quickly kill bacterial cells and are then deactivated in the surrounding without causing environmental problems are of great current interest. Here, we present new biodegradable antibacterial polymers based on polyionenes with inserted ester functions (PBI esters). The polymers are prepared by polycondensation reaction of 1,4-dibromobutene and different tertiary diaminodiesters. The resulting PBI esters are antibacterially active against a wide range of bacterial strains and were found to quickly kill these cells within 1 to 10 min. Because of hydrolysis of the ester groups, the PBI esters are degraded and deactivated in aqueous media. The degradation rate depends on the backbone structure and the pH. The structure of the polymers also controls the deactivation mechanism. While the more hydrophilic polymers require hydrolyses of only 19 to 30% of the ester groups to become practically inactive, the more hydrophobic PBI esters require up to 85% hydrolysis to achieve the same result. Thus, depending on the environmental conditions and the chemical nature, the PBI esters can be active for only 20 min or for at least one week.
Topics: Anti-Bacterial Agents; Bacteria; Biodegradable Plastics; Disinfectants; Esters; Hydrolysis; Hydrophobic and Hydrophilic Interactions; Microbial Sensitivity Tests; Molecular Structure; Polymers
PubMed: 31916737
DOI: 10.1021/acsami.9b19313 -
Chemosphere Dec 2022Wastewater from diverse industrial sectors, agricultural practices and other household activities causes water pollution that result in different environmental issues.... (Review)
Review
Wastewater from diverse industrial sectors, agricultural practices and other household activities causes water pollution that result in different environmental issues. The main goals of wastewater treatment are typically to enhance the purity of wastewater and to enable the disposal of domestic and industrial effluents without endangering human health or causing excessive environmental issues. There were several natural and synthetic materials which have been utilized for wastewater treatment, amongst them polymers gain more importance due to their non-toxicity, economic feasibility, abundant availability of sources, renewability, biocompatibility, biodegradability, etc. The organic polymers such as cellulose, chitin, gelatin, alginates, lignin, dextran and other starch derivatives are the most commonly used natural polymers in wastewater treatments. The unique physical and chemical characteristics of the natural polymers make them become an alternative in wastewater treatments such as membrane filtration, adsorption, coagulation, flocculation and ion-exchange process to remove harmful contaminants such as toxic metals, dyes, medicines, pesticides, and so on. The review article discusses natural polymers and related uses in wastewater treatment. This review mainly focused on the wastewater treatment using natural polymers and the techniques involved for their extraction from natural sources. The recent trends in polymer extraction from the natural sources and the scope for the future research of natural polymers in various sectors are also discussed in detail.
Topics: Cellulose; Chitin; Coloring Agents; Dextrans; Gelatin; Humans; Lignin; Pesticides; Polymers; Starch; Wastewater; Water Pollutants, Chemical; Water Purification
PubMed: 36088969
DOI: 10.1016/j.chemosphere.2022.136368