Self-healing polymers with PEG oligomer side chains based on multiple H-bonding and adhesion properties

Copolymers with a PEG oligomer side chain present high surface energies and adhesion properties; they also can quickly self-heal the crack interfaces spontaneously at ambient temperature.

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Evaluation of the Adhesion Properties of Inorganic Materials with High Surface Energies

Langmuir ◽

10.1021/la048403q ◽

2004 ◽

Vol 20 (23) ◽

pp. 10174-10178 ◽

Cited By ~ 20

Author(s):

Jeong Ho Cho ◽

Dae Ho Lee ◽

Jung Ah Lim ◽

Kilwon Cho ◽

Jung Ho Je ◽

...

Keyword(s):

High Surface ◽

Inorganic Materials ◽

Adhesion Properties ◽

Surface Energies

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Influence of Flexible Side-Chains on the Breathing Phase Transition of Pillared Layer MOFs: A Force Field Investigation

10.26434/chemrxiv.11720679.v1 ◽

2020 ◽

Author(s):

Julian Keupp ◽

Johannes P. Dürholt ◽

Rochus Schmid

Keyword(s):

First Principles ◽

Good Accuracy ◽

Field Investigation ◽

Square Lattice ◽

Side Chain ◽

Second Step ◽

Side Chains ◽

Dynamics Simulations ◽

Complex Phenomena ◽

Closed Pore

The prototypical pillared layer MOFs, formed by a square lattice of paddle- wheel units and connected by dinitrogen pillars, can undergo a breathing phase transition by a “wine-rack” type motion of the square lattice. We studied this not yet fully understood behavior using an accurate first principles parameterized force field (MOF-FF) for larger nanocrystallites on the example of Zn 2 (bdc) 2 (dabco) [bdc: benzenedicarboxylate, dabco: (1,4-diazabicyclo[2.2.2]octane)] and found clear indi- cations for an interface between a closed and an open pore phase traveling through the system during the phase transformation [Adv. Theory Simul. 2019, 2, 11]. In conventional simulations in small supercells this mechanism is prevented by periodic boundary conditions (PBC), enforcing a synchronous transformation of the entire crystal. Here, we extend this investigation to pillared layer MOFs with flexible side-chains, attached to the linker. Such functionalized (fu-)MOFs are experimen- tally known to have different properties with the side-chains acting as fixed guest molecules. First, in order to extend the parameterization for such flexible groups, 1a new parametrization strategy for MOF-FF had to be developed, using a multi- structure force based fit method. The resulting parametrization for a library of fu-MOFs is then validated with respect to a set of reference systems and shows very good accuracy. In the second step, a series of fu-MOFs with increasing side-chain length is studied with respect to the influence of the side-chains on the breathing behavior. For small supercells in PBC a systematic trend of the closed pore volume with the chain length is observed. However, for a nanocrystallite model a distinct interface between a closed and an open pore phase is visible only for the short chain length, whereas for longer chains the interface broadens and a nearly concerted trans- formation is observed. Only by molecular dynamics simulations using accurate force fields such complex phenomena can be studied on a molecular level.

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Dynamic Nanohybrid-Polysaccharide Hydrogels for Soft Wearable Strain Sensing

Sensors ◽

10.3390/s21113574 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3574

Author(s):

Pejman Heidarian ◽

Hossein Yousefi ◽

Akif Kaynak ◽

Mariana Paulino ◽

Saleh Gharaie ◽

...

Keyword(s):

Mechanical Strength ◽

Strain Sensors ◽

Self Healing ◽

Nano Materials ◽

Strain Sensing ◽

Ferric Ions ◽

Research Activity ◽

Adhesion Properties ◽

High Mechanical Strength ◽

The Moment

Electroconductive hydrogels with stimuli-free self-healing and self-recovery (SELF) properties and high mechanical strength for wearable strain sensors is an area of intensive research activity at the moment. Most electroconductive hydrogels, however, consist of static bonds for mechanical strength and dynamic bonds for SELF performance, presenting a challenge to improve both properties into one single hydrogel. An alternative strategy to successfully incorporate both properties into one system is via the use of stiff or rigid, yet dynamic nano-materials. In this work, a nano-hybrid modifier derived from nano-chitin coated with ferric ions and tannic acid (TA/Fe@ChNFs) is blended into a starch/polyvinyl alcohol/polyacrylic acid (St/PVA/PAA) hydrogel. It is hypothesized that the TA/Fe@ChNFs nanohybrid imparts both mechanical strength and stimuli-free SELF properties to the hydrogel via dynamic catecholato-metal coordination bonds. Additionally, the catechol groups of TA provide mussel-inspired adhesion properties to the hydrogel. Due to its electroconductivity, toughness, stimuli-free SELF properties, and self-adhesiveness, a prototype soft wearable strain sensor is created using this hydrogel and subsequently tested.

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Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽

10.3390/polym13111789 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1789

Author(s):

Dmitry Tolmachev ◽

George Mamistvalov ◽

Natalia Lukasheva ◽

Sergey Larin ◽

Mikko Karttunen

Keyword(s):

Glutamic Acid ◽

Chain Length ◽

Chemical Structure ◽

Side Chain ◽

Side Chains ◽

Side Chain Length ◽

Polyelectrolyte Brushes ◽

Grafting Density ◽

The Difference ◽

Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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Unusual Structural Features in the Adduct of Dirhodium Tetraacetate with Lysozyme

International Journal of Molecular Sciences ◽

10.3390/ijms22031496 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1496

Author(s):

Domenico Loreto ◽

Giarita Ferraro ◽

Antonello Merlino

Keyword(s):

Anticancer Agents ◽

Structural Features ◽

Side Chain ◽

Side Chains ◽

Valuable Insight ◽

Experimental Conditions ◽

Egg White Lysozyme ◽

Potential Applications ◽

Model Protein ◽

Hen Egg White

The structures of the adducts formed upon reaction of the cytotoxic paddlewheel dirhodium complex [Rh2(μ-O2CCH3)4] with the model protein hen egg white lysozyme (HEWL) under different experimental conditions are reported. Results indicate that [Rh2(μ-O2CCH3)4] extensively reacts with HEWL:it in part breaks down, at variance with what happens in reactions with other proteins. A Rh center coordinates the side chains of Arg14 and His15. Dimeric Rh–Rh units with Rh–Rh distances between 2.3 and 2.5 Å are bound to the side chains of Asp18, Asp101, Asn93, and Lys96, while a dirhodium unit with a Rh–Rh distance of 3.2–3.4 Å binds the C-terminal carboxylate and the side chain of Lys13 at the interface between two symmetry-related molecules. An additional monometallic fragment binds the side chain of Lys33. These data, which are supported by replicated structural determinations, shed light on the reactivity of dirhodium tetracarboxylates with proteins, providing useful information for the design of new Rh-containing biomaterials with an array of potential applications in the field of catalysis or of medicinal chemistry and valuable insight into the mechanism of action of these potential anticancer agents.

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Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽

10.3390/polym13142286 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2286

Author(s):

Jan Kominek ◽

Martin Zachar ◽

Michal Guzej ◽

Erik Bartuli ◽

Petr Kotrbacek

Keyword(s):

Heat Transfer ◽

Ambient Temperature ◽

Convective Heat ◽

Heat Dissipation ◽

High Surface ◽

Heat Sinks ◽

Fourth Power ◽

Molding Process ◽

Ambient Temperatures ◽

University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

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Synthesis of New Derivatives of BEDT-TTF: Installation of Alkyl, Ethynyl, and Metal-Binding Side Chains and Formation of Tris(BEDT-TTF) Systems

Magnetochemistry ◽

10.3390/magnetochemistry7080110 ◽

2021 ◽

Vol 7 (8) ◽

pp. 110

Author(s):

Songjie Yang ◽

Matteo Zecchini ◽

Andrew Brooks ◽

Sara Krivickas ◽

Desiree Dalligos ◽

...

Keyword(s):

Metal Binding ◽

Tricarboxylic Acid ◽

Metal Salts ◽

Side Chain ◽

Side Chains ◽

Ethynyl Group ◽

X Ray ◽

Transition Metal Salts ◽

Alkyl Side Chains ◽

Derivatives Of

The syntheses of new BEDT-TTF derivatives are described. These comprise BEDT-TTF with one ethynyl group (HC≡C-), with two (n-heptyl) or four (n-butyl) alkyl side chains, with two trans acetal (-CH(OMe)2) groups, with two trans aminomethyl (-CH2NH2) groups, and with an iminodiacetate (-CH2N(CH2CO2−)2 side chain. Three transition metal salts have been prepared from the latter donor, and their magnetic properties are reported. Three tris-donor systems are reported bearing three BEDT-TTF derivatives with ester links to a core derived from benzene-1,3,5-tricarboxylic acid. The stereochemistry and molecular structure of the donors are discussed. X-ray crystal structures of two BEDT-TTF donors are reported: one with two CH(OMe)2 groups and with one a -CH2N(CH2CO2Me)2 side chain.

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Current Understanding of the Structure, Stability and Dynamic Properties of Amyloid Fibrils

International Journal of Molecular Sciences ◽

10.3390/ijms22094349 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4349

Author(s):

Eri Chatani ◽

Keisuke Yuzu ◽

Yumiko Ohhashi ◽

Yuji Goto

Keyword(s):

Amyloid Fibrils ◽

Polypeptide Chain ◽

Dynamic Properties ◽

Protein Molecule ◽

Side Chain ◽

Structure Stability ◽

Side Chains ◽

Precise Control ◽

Functional Amyloids ◽

Structural Architecture

Amyloid fibrils are supramolecular protein assemblies represented by a cross-β structure and fibrous morphology, whose structural architecture has been previously investigated. While amyloid fibrils are basically a main-chain-dominated structure consisting of a backbone of hydrogen bonds, side-chain interactions also play an important role in determining their detailed structures and physicochemical properties. In amyloid fibrils comprising short peptide segments, a steric zipper where a pair of β-sheets with side chains interdigitate tightly is found as a fundamental motif. In amyloid fibrils comprising longer polypeptides, each polypeptide chain folds into a planar structure composed of several β-strands linked by turns or loops, and the steric zippers are formed locally to stabilize the structure. Multiple segments capable of forming steric zippers are contained within a single protein molecule in many cases, and polymorphism appears as a result of the diverse regions and counterparts of the steric zippers. Furthermore, the β-solenoid structure, where the polypeptide chain folds in a solenoid shape with side chains packed inside, is recognized as another important amyloid motif. While side-chain interactions are primarily achieved by non-polar residues in disease-related amyloid fibrils, the participation of hydrophilic and charged residues is prominent in functional amyloids, which often leads to spatiotemporally controlled fibrillation, high reversibility, and the formation of labile amyloids with kinked backbone topology. Achieving precise control of the side-chain interactions within amyloid structures will open up a new horizon for designing useful amyloid-based nanomaterials.

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Enhanced hydrate formation by natural-like hydrophobic side chain amino acids at ambient temperature: A kinetics and morphology investigation

Fuel ◽

10.1016/j.fuel.2021.120828 ◽

2021 ◽

Vol 299 ◽

pp. 120828

Author(s):

Kan Jeenmuang ◽

Chakorn Viriyakul ◽

Katipot Inkong ◽

Hari Prakash Veluswamy ◽

Santi Kulprathipanja ◽

...

Keyword(s):

Amino Acids ◽

Ambient Temperature ◽

Hydrate Formation ◽

Side Chain

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Vertical Orientation of Liquid Crystal on 4-n-Alkyloxyphenoxymethyl-Substituted Polystyrene Containing Liquid Crystal Precursor

Polymers ◽

10.3390/polym13050736 ◽

2021 ◽

Vol 13 (5) ◽

pp. 736

Author(s):

Kyutae Seo ◽

Hyo Kang

Keyword(s):

Molecular Structure ◽

Liquid Crystal ◽

Surface Energy ◽

Polymer Films ◽

Ultraviolet Irradiation ◽

Molar Fraction ◽

Side Chain ◽

Polymer Modification ◽

Vertical Orientation ◽

Surface Energies

We synthesized a series of polystyrene derivatives that were modified with precursors of liquid crystal (LC) molecules, such as 4-ethyloxyphenol (homopolymer PEOP and copolymer PEOP#; # = 20, 40, 60, and 80, where # indicates the molar fraction of 4-ethyloxyphenoxymethyl in the side chain), 4-n-butyloxyphenol (PBOP), 4-n-hexyloxyphenol (PHOP), and 4-n-octyloxyphenol (POOP), via polymer modification reaction to investigate the orientation of LC molecules on polymer films, exhibiting part of the LC molecular structure. LC molecules showed a stable and uniform vertical orientation in LC cells fabricated with polymers that have 4-ethyloxyphenoxymethyl in the range of 40–100 mol%. In addition, similar results were obtained in LC cells fabricated with homopolymers of PEOP, PBOP, PHOP, and POOP. The vertical orientation of LC molecules in LC cells fabricated with polymer films correlated to the surface energy of polymer films. For example, vertical LC orientation was observed when the total surface energies of the polymer films were lower than approximately 43.2 mJ/m2. Good alignment stabilities were observed at 150 °C and 20 J/cm2 of ultraviolet irradiation for LC cells fabricated with PEOP film.

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