Research

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20 pages, 5236 KiB

Open AccessArticle

Radiation-Induced Graft Immobilization (RIGI): Covalent Binding of Non-Vinyl Compounds on Polymer Membranes

by Martin Schmidt, Stefan Zahn, Florian Gehlhaar, Andrea Prager, Jan Griebel, Axel Kahnt, Wolfgang Knolle, Robert Konieczny, Roger Gläser and Agnes Schulze

Polymers 2021, 13(11), 1849; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13111849 - 02 Jun 2021

Cited by 12 | Viewed by 2999

Abstract

Radiation-induced graft immobilization (RIGI) is a novel method for the covalent binding of substances on polymeric materials without the use of additional chemicals. In contrast to the well-known radiation-induced graft polymerization (RIGP), RIGI can use non-vinyl compounds such as small and large functional [...] Read more.

Radiation-induced graft immobilization (RIGI) is a novel method for the covalent binding of substances on polymeric materials without the use of additional chemicals. In contrast to the well-known radiation-induced graft polymerization (RIGP), RIGI can use non-vinyl compounds such as small and large functional molecules, hydrophilic polymers, or even enzymes. In a one-step electron-beam-based process, immobilization can be performed in a clean, fast, and continuous operation mode, as required for industrial applications. This study proposes a reaction mechanism using polyvinylidene fluoride (PVDF) and two small model molecules, glycine and taurine, in aqueous solution. Covalent coupling of single molecules is achieved by radical recombination and alkene addition reactions, with water radiolysis playing a crucial role in the formation of reactive solute species. Hydroxyl radicals contribute mainly to the immobilization, while solvated electrons and hydrogen radicals play a minor role. Release of fluoride is mainly induced by direct ionization of the polymer and supported by water. Hydrophobic chains attached to cations appear to enhance the covalent attachment of solutes to the polymer surface. Computational work is complemented by experimental studies, including X-ray photoelectron spectroscopy (XPS) and fluoride high-performance ion chromatography (HPIC). Full article

(This article belongs to the Special Issue Advances in Surface Functionalization of Polymer Nanostructures)

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Review

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42 pages, 9634 KiB

Open AccessReview

Advances in Functionalized Photosensitive Polymeric Nanocarriers

by Maritza Fernández and Jahir Orozco

Polymers 2021, 13(15), 2464; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13152464 - 27 Jul 2021

Cited by 26 | Viewed by 4719

Abstract

The synthesis of light-responsive nanocarriers (LRNs) with a variety of surface functional groups and/or ligands has been intensively explored for space-temporal controlled cargo release. LRNs have been designed on demand for photodynamic-, photothermal-, chemo-, and radiotherapy, protected delivery of bioactive molecules, such as [...] Read more.

The synthesis of light-responsive nanocarriers (LRNs) with a variety of surface functional groups and/or ligands has been intensively explored for space-temporal controlled cargo release. LRNs have been designed on demand for photodynamic-, photothermal-, chemo-, and radiotherapy, protected delivery of bioactive molecules, such as smart drug delivery systems and for theranostic duties. LRNs trigger the release of cargo by a light stimulus. The idea of modifying LRNs with different moieties and ligands search for site-specific cargo delivery imparting stealth effects and/or eliciting specific cellular interactions to improve the nanosystems’ safety and efficacy. This work reviews photoresponsive polymeric nanocarriers and photo-stimulation mechanisms, surface chemistry to link ligands and characterization of the resultant nanosystems. It summarizes the interesting biomedical applications of functionalized photo-controlled nanocarriers, highlighting the current challenges and opportunities of such high-performance photo-triggered delivery systems. Full article

(This article belongs to the Special Issue Advances in Surface Functionalization of Polymer Nanostructures)

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28 pages, 6991 KiB

Open AccessReview

Is Poly(methyl methacrylate) (PMMA) a Suitable Substrate for ALD?: A Review

by Marta Adriana Forte, Ricardo Manuel Silva, Carlos José Tavares and Rui Ferreira e Silva

Polymers 2021, 13(8), 1346; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13081346 - 20 Apr 2021

Cited by 22 | Viewed by 10150

Abstract

Poly (methyl methacrylate) (PMMA) is a thermoplastic synthetic polymer, which displays superior characteristics such as transparency, good tensile strength, and processability. Its performance can be improved by surface engineering via the use of functionalized thin film coatings, resulting in its versatility across a [...] Read more.

Poly (methyl methacrylate) (PMMA) is a thermoplastic synthetic polymer, which displays superior characteristics such as transparency, good tensile strength, and processability. Its performance can be improved by surface engineering via the use of functionalized thin film coatings, resulting in its versatility across a host of applications including, energy harvesting, dielectric layers and water purification. Modification of the PMMA surface can be achieved by atomic layer deposition (ALD), a vapor-phase, chemical deposition technique, which permits atomic-level control. However, PMMA presents a challenge for ALD due to its lack of active surface sites, necessary for gas precursor reaction, nucleation, and subsequent growth. The purpose of this review is to discuss the research related to the employment of PMMA as either a substrate, support, or masking layer over a range of ALD thin film growth techniques, namely, thermal, plasma-enhanced, and area-selective atomic layer deposition. It also highlights applications in the selected fields of flexible electronics, biomaterials, sensing, and photocatalysis, and underscores relevant characterization techniques. Further, it concludes with a prospective view of the role of ALD in PMMA processing. Full article

(This article belongs to the Special Issue Advances in Surface Functionalization of Polymer Nanostructures)

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