Temporally Controlled Ultrasonication‐Mediated Atom Transfer Radical Polymerization in Miniemulsion

Surface Functionalization with Polymer Brushes via Surface-Initiated Atom Transfer Radical Polymerization: Synthesis, Applications, and Current Challenges

Polymer brushes have received great attention in recent years due to their distinctive properties and wide range of applications. The synthesis of polymer brushes typically employs surface-initiated atom transfer radical polymerization (SI-ATRP) techniques. To realize the control of the polymerization process in different environments, various SI-ATRP techniques triggered by different stimuli have been developed. This review focuses on the latest developments in different stimuli-triggered SI-ATRP methods, such as electrochemically mediated, photoinduced, enzyme-assisted, mechanically controlled, and organocatalyzed ATRP. Additionally, SI-ATRP technology triggered by a combination of multiple stimuli sources is also discussed. Furthermore, the applications of polymer brushes in lubrication, biological applications, antifouling, and catalysis are also systematically summarized and discussed. Despite the advancements in the synthesis of various types of 1D, 2D, and 3D polymer brushes via controlled radical polymerization, contemporary challenges remain in the quest for more efficient and straightforward synthetic protocols that allow for precise control over the composition, structure, and functionality of polymer brushes. We anticipate the readers could promote the understanding of surface functionalization based on ATRP-mediated polymer brushes and envision future directions for their application in surface coating technologies.

Engineering poly(ethylene glycol) particles for targeted drug delivery

Poly(ethylene glycol) (PEG) is considered to be the "gold standard" among the stealth polymers employed for drug delivery. Using PEG to modify or engineer particles has thus gained increasing interest because of the ability to prolong blood circulation time and reduce nonspecific biodistribution of particles in vivo, owing to the low fouling and stealth properties of PEG. In addition, endowing PEG-based particles with targeting and drug-loading properties is essential to achieve enhanced drug accumulation at target sites in vivo. In this feature article, we focus on recent work on the synthesis of PEG particles, in which PEG is the main component in the particles. We highlight different synthesis methods used to generate PEG particles, the influence of the physiochemical properties of PEG particles on their stealth and targeting properties, and the application of PEG particles in targeted drug delivery.

Layer-by-Layer Self-Assembly Coating for Multi-Functionalized Fabrics: A Scientometric Analysis in CiteSpace (2005-2021)

Surface-engineered coatings have been increasingly applied to functionalize fabrics due to the ease of deposition of the coatings and their effectiveness in endowing the fabric with abundant properties. Among the surface modification methods, layer-by-layer (LbL) self-assembly has emerged as an important approach for creating multifunctional surfaces on fabrics. In this review, bibliometric analysis with the visualization analysis of LbL self-assembly coatings on fabrics was performed on publications extracted from the Web of Science (WOS) from 2005 to 2021 based on the CiteSpace software. The analysis results showed that research on LbL self-assembly coatings on fabrics has attracted much attention, and this technique has plentiful and flexible applications. Moreover, research on the LbL self-assembly method in the field of functionalization of fabrics has been summarized, which include flame retardant fabric, antibacterial fabric, ultraviolet resistant fabric, hydrophobic fabric and electromagnetic shielding fabric. It was found that the functionalization of the fabric has been changing from singularity to diversification. Based on the review, several future research directions can be proposed. The weatherability, comfort, cost and environmental friendliness should be considered when the multifunctional coatings are designed.

Toward Green Atom Transfer Radical Polymerization: Current Status and Future Challenges

Reversible-deactivation radical polymerizations (RDRPs) have revolutionized synthetic polymer chemistry. Nowadays, RDRPs facilitate design and preparation of materials with controlled architecture, composition, and functionality. Atom transfer radical polymerization (ATRP) has evolved beyond traditional polymer field, enabling synthesis of organic-inorganic hybrids, bioconjugates, advanced polymers for electronics, energy, and environmentally relevant polymeric materials for broad applications in various fields. This review focuses on the relation between ATRP technology and the 12 principles of green chemistry, which are paramount guidelines in sustainable research and implementation. The green features of ATRP are presented, discussing the environmental and/or health issues and the challenges that remain to be overcome. Key discoveries and recent developments in green ATRP are highlighted, while providing a perspective for future opportunities in this area.

Ultrasound in cellulose-based hydrogel for biomedical use: From extraction to preparation

As the most abundant natural polymer on the pl anet, cellulose has a wide range of applications in the biomedical field. Cellulose-based hydrogels further expand the applications of this class of biomaterials. However, a number of publications and technical reports are mainly about traditional preparation methods. Sonochemistry offers a simple and green route to material synthesis with the biomedical application of ultrasound. The tiny acoustic bubbles, produced by the propagating sound wave, enclose an incredible facility where matter interact among at energy as high as 13 eV to spark extraordinary chemical reactions. Ultrasonication not only improves the efficiency of cellulose extraction from raw materials, but also influences the hydrogel preparation process. The primary objective of this article is to review the literature concerning the biomedical cellulose-based hydrogel prepared via sonochemistry and application of ultrasound for hydrogel. An innovated category of recent generations of hydrogel materials prepared via ultrasound was also presented in some details.

Sonochemistry-assisted photocontrolled atom transfer radical polymerization enabled by manganese carbonyl

Sonochemistry-assisted photocontrolled atom transfer radical polymerization (SAP-ATRP) is developed to circumvent the problem caused by the low penetration depth of light.

Aqueous emulsion polymerizations of methacrylates and styrene via reversible complexation mediated polymerization (RCMP)

Aqueous emulsion polymerization via reversible complexation mediated living radical polymerization yielded low-dispersity poly(methyl methacrylate)s and polystyrenes.

Facile One-Step Fabrication of Phthalocyanine-Graphene-Bacterial-Cellulose Nanocomposite with Superior Catalytic Performance

It is generally accepted that the convenient fabrication of a metal phthalocyanine-based heterogeneous catalyst with superior catalytic activity is crucial for its application. Herein, a novel and versatile ultrasonic-assisted biosynthesis approach (conducting ultrasonic treatment during biosynthesis process) was tactfully adopted for the direct immobilization of a sulfonated cobalt phthalocyanine (PcS) catalyst onto a graphene-bacterial cellulose (GBC) substrate without any modification. The prepared phthalocyanine-graphene-bacterial-cellulose nanocomposite, PcS@GBC, was characterized by field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS). The catalytic activity of the PcS@GBC was evaluated based on its catalytic oxidation performance to dye solution, with H₂O₂ used as an oxidant. More than a 140% increase of dye removal percentage for the PcS@GBC heterogeneous catalyst was found compared with that of PcS. The unique hierarchical architecture of the GBC substrate and the strong interaction between PcS and graphene, which were verified experimentally by ultraviolet-visible light spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FT-IR) and theoretically by density functional theory (DFT) calculation, were synergistically responsible for the substantial enhancement of catalytic activity. The accelerated formation of the highly reactive hydroxyl radical (·OH) for PcS@GBC was directly evidenced by the electron paramagnetic resonance (EPR) spin-trapping technique. A possible catalytic oxidation mechanism for the PcS@GBC-H₂O₂ system was illustrated. This work provides a new insight into the design and construction of a highly reactive metal phthalocyanine-based catalyst, and the practical application of this functional nanomaterial in the field of environmental purification is also promising.

Low Ppm Atom Transfer Radical Polymerization in (Mini)Emulsion Systems

In the last decade, unceasing interest in atom transfer radical polymerization (ATRP) has been noted, especially in aqueous dispersion systems. Emulsion or miniemulsion is a preferred environment for industrial polymerization due to easier heat dissipation and lower production costs associated with the use of water as a dispersant. The main purpose of this review is to summarize ATRP methods used in emulsion media with different variants of initiating systems. A comparison of a dual over single catalytic approache by interfacial and ion pair catalysis is presented. In addition, future development directions for these methods are suggested for better use in biomedical and electronics industries.

Surface Modifications of Poly(Ether Ether Ketone) via Polymerization Methods-Current Status and Future Prospects

Surface modification of poly(ether ether ketone) (PEEK) aimed at applying it as a bone implant material aroused the unflagging interest of the research community. In view of the development of implantology and the growing demand for new biomaterials, increasing biocompatibility and improving osseointegration are becoming the primary goals of PEEK surface modifications. The main aim of this review is to summarize the use of polymerization methods and various monomers applied for surface modification of PEEK to increase its bioactivity, which is a critical factor for successful applications of biomedical materials. In addition, the future directions of PEEK surface modifications are suggested, pointing to low-ppm surface-initiated atom transfer radical polymerization (SI-ATRP) as a method with unexplored capacity for flat surface modifications.

Role of External Field in Polymerization: Mechanism and Kinetics

The past decades have witnessed an increasing interest in developing advanced polymerization techniques subjected to external fields. Various physical modulations, such as temperature, light, electricity, magnetic field, ultrasound, and microwave irradiation, are noninvasive means, having superb but distinct abilities to regulate polymerizations in terms of process intensification and spatial and temporal controls. Gas as an emerging regulator plays a distinctive role in controlling polymerization and resembles a physical regulator in some cases. This review provides a systematic overview of seven types of external-field-regulated polymerizations, ranging from chain-growth to step-growth polymerization. A detailed account of the relevant mechanism and kinetics is provided to better understand the role of each external field in polymerization. In addition, given the crucial role of modeling and simulation in mechanisms and kinetics investigation, an overview of model construction and typical numerical methods used in this field as well as highlights of the interaction between experiment and simulation toward kinetics in the existing systems are given. At the end, limitations and future perspectives for this field are critically discussed. This state-of-the-art research progress not only provides the fundamental principles underlying external-field-regulated polymerizations but also stimulates new development of advanced polymerization methods.

Ultrasound-Mediated Atom Transfer Radical Polymerization (ATRP)

Ultrasonic agitation is an external stimulus, rapidly developed in recent years in the atom transfer radical polymerization (ATRP) approach. This review presents the current state-of-the-art in the application of ultrasound in ATRP, including an initially-developed, mechanically-initiated solution with the use of piezoelectric nanoparticles, that next goes to the ultrasonication-mediated method utilizing ultrasound as a factor for producing radicals through the homolytic cleavage of polymer chains, or the sonolysis of solvent or other small molecules. Future perspectives in the field of ultrasound in ATRP are presented, focusing on the preparation of more complex architectures with highly predictable molecular weights and versatile properties. The challenges also include biohybrid materials. Recent advances in the ultrasound-mediated ATRP point out this approach as an excellent tool for the synthesis of advanced materials with a wide range of potential industrial applications.

Surface-Initiated Atom Transfer Radical Polymerization for the Preparation of Well-Defined Organic-Inorganic Hybrid Nanomaterials

Surface-initiated atom transfer radical polymerization (SI-ATRP) is a powerful tool that allows for the synthesis of organic-inorganic hybrid nanomaterials with high potential applications in many disciplines. This review presents synthetic achievements and modifications of nanoparticles via SI-ATRP described in literature last decade. The work mainly focuses on the research development of silica, gold and iron polymer-grafted nanoparticles as well as nature-based materials like nanocellulose. Moreover, typical single examples of nanoparticles modification, i.e., ZnO, are presented. The organic-inorganic hybrid systems received according to the reversible deactivation radical polymerization (RDRP) approach with drastically reduced catalyst complex concentration indicate a wide range of applications of materials including biomedicine and microelectronic devices.