Layer-by-Layer Deposition: A Promising Environmentally Benign Flame-Retardant Treatment for Cotton, Polyester, Polyamide and Blended Textiles

A detailed review of recent developments of layer-by-layer (LbL) deposition as a promising approach to reduce flammability of the most widely used fibers (cotton, polyester, polyamide and their blends) is presented. LbL deposition is an emerging green technology, showing numerous advantages over current commercially available finishing processes due to the use of water as a solvent for a variety of active substances. For flame-retardant (FR) purposes, different ingredients are able to build oppositely charged layers at very low concentrations in water (e.g., small organic molecules and macromolecules from renewable sources, inorganic compounds, metallic or oxide colloids, etc.). Since the layers on a textile substrate are bonded with pH and ion-sensitive electrostatic forces, the greatest technological drawback of LbL deposition for FR finishing is its non-resistance to washing cycles. Several possibilities of laundering durability improvements by different pre-treatments, as well as post-treatments to form covalent bonds between the layers, are presented in this review.

Download Full-text

Layer-by-layer deposition of oppositely charged polyelectrolytes on the surface of condensed DNA particles

Nucleic Acids Research ◽

10.1093/nar/27.15.3090 ◽

1999 ◽

Vol 27 (15) ◽

pp. 3090-3095 ◽

Cited By ~ 70

Author(s):

V. S. Trubetskoy ◽

A. Loomis ◽

J. E. Hagstrom ◽

V. G. Budker ◽

J. A. Wolff

Keyword(s):

Layer By Layer ◽

Layer Deposition ◽

Oppositely Charged ◽

Condensed Dna

Download Full-text

Nanoparticle-Doped Hybrid Polyelectrolyte Microcapsules with Controlled Photoluminescence for Potential Bioimaging Applications

Polymers ◽

10.3390/polym13234076 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4076

Author(s):

Galina Nifontova ◽

Victor Krivenkov ◽

Mariya Zvaigzne ◽

Anton Efimov ◽

Evgeny Korostylev ◽

...

Keyword(s):

Semiconductor Nanocrystals ◽

Emission Spectra ◽

Fluorescent Imaging ◽

Water Soluble ◽

Layer By Layer ◽

Layer Deposition ◽

Theranostic Agents ◽

Further Development ◽

Oppositely Charged ◽

Transformation Processes

Fluorescent imaging is widely used in the diagnosis and tracking of the distribution, interaction, and transformation processes at molecular, cellular, and tissue levels. To be detectable, delivery systems should exhibit a strong and bright fluorescence. Quantum dots (QDs) are highly photostable fluorescent semiconductor nanocrystals with wide absorption spectra and narrow, size-tunable emission spectra, which make them suitable fluorescent nanolabels to be embedded into microparticles used as bioimaging and theranostic agents. The layer-by-layer deposition approach allows the entrapping of QDs, resulting in bright fluorescent microcapsules with tunable surface charge, size, rigidity, and functional properties. Here, we report on the engineering and validation of the structural and photoluminescent characteristics of nanoparticle-doped hybrid microcapsules assembled by the deposition of alternating oppositely charged polyelectrolytes, water-soluble PEGylated core/shell QDs with a cadmium selenide core and a zinc sulfide shell (CdSe/ZnS), and carboxylated magnetic nanoparticles (MNPs) onto calcium carbonate microtemplates. The results demonstrate the efficiency of the layer-by-layer approach to designing QD-, MNP-doped microcapsules with controlled photoluminescence properties, and pave the way for the further development of next-generation bioimaging agents based on hybrid materials for continuous fluorescence imaging.

Download Full-text

Top-Down Polyelectrolytes for Membrane-Based Post-Combustion CO2 Capture

Molecules ◽

10.3390/molecules25020323 ◽

2020 ◽

Vol 25 (2) ◽

pp. 323 ◽

Cited By ~ 3

Author(s):

Daria Nikolaeva ◽

Patricia Luis

Keyword(s):

Large Scale ◽

Polymer Materials ◽

Layer By Layer ◽

Solvent Casting ◽

Top Down ◽

Layer Deposition ◽

Recent Developments ◽

Synthesis And Processing ◽

Cost Efficient ◽

Physical And Chemical

Polymer-based CO2 selective membranes offer an energy efficient method to separate CO2 from flue gas. ‘Top-down’ polyelectrolytes represent a particularly interesting class of polymer materials based on their vast synthetic flexibility, tuneable interaction with gas molecules, ease of processability into thin films, and commercial availability of precursors. Recent developments in their synthesis and processing are reviewed herein. The four main groups of post-synthetically modified polyelectrolytes discern ionised neutral polymers, cation and anion functionalised polymers, and methacrylate-derived polyelectrolytes. These polyelectrolytes differentiate according to the origin and chemical structure of the precursor polymer. Polyelectrolytes are mostly processed into thin-film composite (TFC) membranes using physical and chemical layer deposition techniques such as solvent-casting, Langmuir-Blodgett, Layer-by-Layer, and chemical grafting. While solvent-casting allows manufacturing commercially competitive TFC membranes, other methods should still mature to become cost-efficient for large-scale application. Many post-synthetically modified polyelectrolytes exhibit outstanding selectivity for CO2 and some overcome the Robeson plot for CO2/N2 separation. However, their CO2 permeance remain low with only grafted and solvent-casted films being able to approach the industrially relevant performance parameters. The development of polyelectrolyte-based membranes for CO2 separation should direct further efforts at promoting the CO2 transport rates while maintaining high selectivities with additional emphasis on environmentally sourced precursor polymers.

Download Full-text

Large-Scale Continuous Immersion System for Layer-by-Layer Deposition of Flame Retardant and Conductive Nanocoatings on Fabric

Industrial & Engineering Chemistry Research ◽

10.1021/ie500122u ◽

2014 ◽

Vol 53 (15) ◽

pp. 6409-6416 ◽

Cited By ~ 49

Author(s):

Arturo J. Mateos ◽

Amanda A. Cain ◽

Jaime C. Grunlan

Keyword(s):

Flame Retardant ◽

Large Scale ◽

Layer By Layer ◽

Layer Deposition

Download Full-text

A Flame-Retardant Phytic-Acid-Based LbL-Coating for Cotton Using Polyvinylamine

Polymers ◽

10.3390/polym12051202 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1202 ◽

Cited By ~ 1

Author(s):

Olga Zilke ◽

Dennis Plohl ◽

Klaus Opwis ◽

Thomas Mayer-Gall ◽

Jochen Stefan Gutmann

Keyword(s):

Carbon Monoxide ◽

Fourier Transform ◽

Flame Retardant ◽

Phytic Acid ◽

Layer By Layer ◽

Afterglow Time ◽

Peak Heat Release Rate ◽

Amine Groups ◽

Microscale Combustion Calorimetry ◽

Oppositely Charged

Phytic acid (PA), as a natural source of phosphorus, was immobilized on cotton (CO) in a layer-by-layer (LbL) approach with polyvinylamine (PVAm) as the oppositely charged electrolyte to create a partly bio-based flame-retardant finish. PVAm was employed as a synthetic nitrogen source with the highest density of amine groups of all polymers. Vertical flame tests revealed a flame-retardant behavior with no afterflame and afterglow time for a coating of 15 bilayers (BL) containing 2% phosphorus and 1.4% nitrogen. The coating achieved a molar P:N ratio of 3:5. Microscale combustion calorimetry (MCC) analyses affirmed the flame test findings by a decrease in peak heat release rate (pkHRR) by more than 60% relative to unfinished CO. Thermogravimetric analyses (TGA) and MCC measurements exhibited a shifted CO peak to lower temperatures indicating proceeding reactions to form an isolating char on the surface. Fourier transform infrared spectroscopy (FTIR) coupled online with a TGA system, allowed the identification of a decreased amount of acrolein, methanol, carbon monoxide and formaldehyde during sample pyrolysis and a higher amount of released water. Thereby the toxicity of released volatiles was reduced. Our results prove that PA enables a different reaction by catalyzing cellulosic dehydration, which results in the formation of a protective char on the surface of the burned fabric.

Download Full-text