Alginate polyelectrolyte complexes with cationic hydroxyethyl cellulose derivatives: Role of the block structure

2006 ◽  
Vol 48 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Yu. A. Shchipunov ◽  
I. V. Postnova
Keyword(s):  
Block Structure ◽  
Hydroxyethyl Cellulose ◽  
Cellulose Derivatives ◽  
Polyelectrolyte Complexes

scholarly journals Film formation and foamability of cellulose derivatives: Influence of co-binders and substrate properties on coating holdout

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 597-613
Author(s):  
Johanna Lyytikäinen ◽  
Sami-Seppo Ovaska ◽  
Isto Heiskanen ◽  
Kaj Backfolk
Keyword(s):  
Film Formation ◽  
Hydrophobic Surface ◽  
Hydroxyethyl Cellulose ◽  
Cellulose Derivatives ◽  
Hydrophobically Modified ◽  
Substrate Properties ◽  
Foam Forming ◽  
Water Holding ◽  
Good Coating

Foams were prepared from hydrophobically modified ethyl(hydroxyethyl) cellulose (EHEC), methyl nanocellulose, and native microfibrillated cellulose (MFC). Their film- and foam-forming abilities, stabilities, and suitabilities for foam coating on different substrates were investigated. The role of EHEC as a polymeric stabilizing agent was also studied. The EHEC-MFC foams showed greater stability and water-holding ability under pressurized dewatering than MFC foams prepared in the presence of a surfactant. A foam could be created with methyl nanocellulose without any foaming agent. Selected nanocellulose gels and foam formulations were used to coat various substrates. The surface was efficiently closed by gel and foam coatings prepared from the methyl nanocellulose and EHEC solutions, which was ascribed to good coating holdout. Coatings on papers with different levels of smoothness/density and hydrophobicity/ hydrophilicity confirmed that foam-substrate interactions affected the coat quality. The air permeance was reduced by 99% and 64% with a methyl nanocellulose coating and an EHEC-MFC coating, respectively. An EHEC-MFC coating created a hydrophobic surface on a hydrophilic substrate, and methyl nanocellulose improved the oil resistance even at a low coat weight.

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

scholarly journals Skin and bubble formation in films made of methyl nanocellulose, hydrophobically modified ethyl(hydroxyethyl)cellulose and microfibrillated cellulose

Cellulose ◽  
2020 ◽  
Author(s):  
Johanna Lyytikäinen ◽  
Maria Morits ◽  
Monika Österberg ◽  
Isto Heiskanen ◽  
Kaj Backfolk
Keyword(s):  
Methyl Cellulose ◽  
Microfibrillated Cellulose ◽  
Hydroxyethyl Cellulose ◽  
Effect Of Temperature ◽  
Cellulose Derivatives ◽  
Air Bubbles ◽  
Oxygen Transmission Rate ◽  
Hydrophobically Modified ◽  
Film Forming ◽  
Ethyl Hydroxyethyl Cellulose

AbstractThe use of nanomaterials and polymers from renewable resources is important in the search for sustainable alternatives to plastic-based packaging materials and films. In this work, self-supporting thin films prepared from derivatized and non-derivatized nanocellulose and cellulose derivatives were studied. The effect of drying temperature on the film-forming behavior of compositions comprising hydrophobically modified ethyl(hydroxyethyl)cellulose (EHEC), native microfibrillated cellulose (MFC) and nanocellulose made from methyl cellulose was determined. The interaction between the components was assessed from viscosity measurements made at different temperatures, the result being linked to a thermal-dependent association during liquid evaporation, and the subsequent barrier and film-forming properties. The effect of temperature on suspensions was clearly different between the materials, confirming that there were differences in interaction and association between EHEC–MFC and methyl nanocellulose–MFC compositions. The amphiphilic EHEC affected both the suspension homogeneity and the film properties. Air bubbles were formed under certain conditions and composition particularly in MFC films, dependent on the drying procedure. The presence of air bubbles did not affect the oxygen transmission rate or the oil and grease resistance. An increasing amount of MFC improved the oxygen barrier properties of the films.

scholarly journals Cellulose as a Natural Emulsifier: From Nanocelluloses to Macromolecules

2021 ◽  
Author(s):  
Carolina Costa ◽  
Bruno Medronho ◽  
Björn Lindman ◽  
Håkan Edlund ◽  
Magnus Norgren
Keyword(s):  
Structural Features ◽  
Cellulose Derivatives ◽  
Structural Anisotropy ◽  
Cellulose Nanoparticles ◽  
Oil Water ◽  
Natural Emulsifier

During the last decade, cellulose structural features have been revisited, with particular focus on its structural anisotropy (amphiphilicity) and interactions determining its recalcitrance to dissolution. Evidences for cellulose amphiphilicity are patent, for instance, in its capacity to adsorb at oil–water interfaces, thus being capable of stabilizing emulsions. This behavior is observable in all its forms, from cellulose nanoparticles to macromolecules. This chapter is divided into two main parts; first, the fundamentals of emulsion formation and stabilization will be introduced, particularly focusing on the role of natural emulsifiers. Secondly, the emerging role of cellulose as a natural emulsifier, where the ability of cellulose to form and stabilize emulsions is revisited, from cellulose nanoparticles (Pickering-like effect) to macromolecules (i.e., cellulose derivatives and native molecular cellulose).

The role of MFC and hydrophobically modified ethyl(hydroxyethyl)cellulose in film formation and the barrier properties of methyl nanocellulose film

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Johanna Lyytikäinen ◽  
Sami-Seppo Ovaska ◽  
Isto Heiskanen ◽  
Kaj Backfolk
Keyword(s):  
Contact Angle ◽  
High Performance ◽  
Film Formation ◽  
Barrier Properties ◽  
Hydroxyethyl Cellulose ◽  
Hydrophobically Modified ◽  
Coated Materials ◽  
Ethyl Hydroxyethyl Cellulose ◽  
Nanocellulose Film

Abstract There is currently a great demand for sustainable and bio-derived coatings for fiber-based packaging materials, which are technically implementable with a high performance. The aim of this work was to investigate the grease resistance of coatings prepared from methyl nanocellulose when applied on paperboard. Co-additives selected from native microfibrillated cellulose (MFC) and hydrophobically modified ethyl(hydroxyethyl)cellulose (EHEC) were used in order to determine their impact on film formation and crack resistance for folds. Small and moderate coat weights were applied in order to determine the critical coat weight for the barrier properties. It was found that high grease resistance can be achieved with methyl nanocellulose and a combination of methyl nanocellulose and MFC coatings. Contact angle determinations for water on uncoated and coated materials showed that EHEC-MFC films have a very high contact angle which is due to both the surface chemistry and roughness. This indicates and confirms that EHEC may facilitate the wetting of oil and greases. Methyl nanocellulose mixed with hydrophobically modified EHEC significantly changed the barrier properties indicating a change in the film formation.

Formation of polyelectrolyte complexes between cellulose derivatives and their blood compatibility

1986 ◽  
Vol 31 (8) ◽  
pp. 2491-2500 ◽  
Author(s):  
Hiraku Ito ◽  
Toru Shibata ◽  
Takeaki Miyamoto ◽  
Yasuharu Noishiki ◽  
Hiroshi Inagaki
Keyword(s):  
Blood Compatibility ◽  
Cellulose Derivatives ◽  
Polyelectrolyte Complexes
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