Amplified photo-responses in sequentially polymerized azobenzene-containing polymer networks: the role of isomer interconnection

2020 ◽  
Vol 11 (12) ◽  
pp. 1998-2005
Author(s):  
Chenzhe Li ◽  
Hyunsu Kim ◽  
Jongwon An ◽  
Maenghyo Cho
Keyword(s):  
Polymer Networks

Sequentially polymerized azobenzene-containing polymer networks with isomer-interconnected features can greatly enhance photo-actuation responses.

Exploring secondary interactions and the role of temperature in moisture-contaminated polymer networks through molecular simulations

Soft Matter ◽  
2021 ◽  
Vol 17 (10) ◽  
pp. 2942-2956
Author(s):  
Rishabh D. Guha ◽  
Ogheneovo Idolor ◽  
Katherine Berkowitz ◽  
Melissa Pasquinelli ◽  
Landon R. Grace
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Temperature Variation ◽  
Polymer Networks ◽  
Molecular Simulations ◽  
Effect Of Temperature ◽  
Secondary Interactions ◽  
Dynamics Simulations ◽  
Secondary Bonding

We investigated the effect of temperature variation on the secondary bonding interactions between absorbed moisture and epoxies with different morphologies using molecular dynamics simulations.

scholarly journals A Guide through the Dental Dimethacrylate Polymer Network Structural Characterization and Interpretation of Physico-Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4057 ◽  
Author(s):  
Izabela Maria Barszczewska-Rybarek
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Structural Parameters ◽  
Polymer Network ◽  
Polymer Networks ◽  
Impact Resistance ◽  
Organic Matrices ◽  
Dental Restorative

Material characterization by the determination of relationships between structure and properties at different scales is essential for contemporary material engineering. This review article provides a summary of such studies on dimethacrylate polymer networks. These polymers serve as photocuring organic matrices in the composite dental restorative materials. The polymer network structure was discussed from the perspective of the following three aspects: the chemical structure, molecular structure (characterized by the degree of conversion and crosslink density (chemical as well as physical)), and supramolecular structure (characterized by the microgel agglomerate dimensions). Instrumental techniques and methodologies currently used for the determination of particular structural parameters were summarized. The influence of those parameters as well as the role of hydrogen bonding on basic mechanical properties of dimethacrylate polymer networks were finally demonstrated. Mechanical strength, modulus of elasticity, hardness, and impact resistance were discussed. The issue of the relationship between chemical structure and water sorption was also addressed.

scholarly journals Optical and Photoelectrochemical Investigation of Mixed Photoactive Poly 2,2’,5,2’’ ter-thiophene and Poly 2,2 bithiophene. Role of Intermixed Phases Created By the Co-electro-polymerization Process

2019 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Kasem K. Kasem ◽  
Monica Schultz ◽  
Sarah H. Osman
Keyword(s):  
Electrochemical Impedance ◽  
Polymer Networks ◽  
Outcome Data ◽  
Polymeric Films ◽  
Polymerization Process ◽  
Density Of State ◽  
Barrier Energy ◽  
Direct Band ◽  
P Type

Fluorine-doped tin oxide (FTO) electrodes modified with polymeric films of poly 2,2 bithiophene (PBth) and/or poly 2,2’,5,2’’-terthiophene (PTerth) were subjected to optical, photoelectrochemical (PEC), and electrochemical impedance spectroscopy (EIS) studies. Electropolymerization of mixed monomers containing bi-thiophene (Bth) and ter-thiophene (Terth) with different ratios resulted in the formation of intermixed phases. The recorded optical and PEC and EIS outcome data show that these intermixed polymer networks do not follow a monotonic relationship with the monomer ratios used to generate them. Optical studies indicate the formation of indirect and direct band gaps in the intermixed phases. Films generated in mixed monomers have greater energy-band tails than those generated from pure monomers. PEC studies indicated that these intermixed phases possess p-p type hole accumulations, evident from the initial sharp rise in photocurrent. EIS results did not support linear relationship between the percent of Bth in monomer mixture and the dielectric-related properties such as barrier energy Wm, hopping frequency (ω hopping), electrical conductivity (σ), and density of state at Fermi level N (EF).

scholarly journals Microbiological-Chemical Sourced Chondroitin Sulfates Protect Neuroblastoma SH-SY5Y Cells against Oxidative Stress and Are Suitable for Hydrogel-Based Controlled Release

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1816
Author(s):  
Emiliano Bedini ◽  
Alfonso Iadonisi ◽  
Chiara Schiraldi ◽  
Laura Colombo ◽  
Diego Albani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Neuroprotective Effect ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Ethical Concerns ◽  
Chondroitin Sulfates ◽  
Sulfation Pattern ◽  
Pre Treatment ◽  
Set Up

Chondroitin sulfates (CS) are a class of sulfated glycosaminoglycans involved in many biological processes. Several studies reported their protective effect against neurodegenerative conditions like Alzheimer’s disease. CS are commonly derived from animal sources, but ethical concerns, the risk of contamination with animal proteins, and the difficulty in controlling the sulfation pattern have prompted research towards non-animal sources. Here we exploited two microbiological-chemical sourced CS (i.e., CS-A,C and CS-A,C,K,L) and Carbopol 974P NF/agarose semi-interpenetrating polymer networks (i.e., P.NaOH.0 and P.Ethanol.0) to set up a release system, and tested the neuroprotective role of released CS against H2O2-induced oxidative stress. After assessing that our CS (1–100 µM) require a 3 h pre-treatment for neuroprotection with SH-SY5Y cells, we evaluated whether the autoclave type (i.e., N- or B-type) affects hydrogel viscoelastic properties. We selected B-type autoclaves and repeated the study after loading CS (1 or 0.1 mg CS/0.5 mL gel). After loading 1 mg CS/0.5 mL gel, we evaluated CS release up to 7 days by 1,9-dimethylmethylene blue (DMMB) assay and verified the neuroprotective role of CS-A,C (1 µM) in the supernatants. We observed that CS-A,C exhibits a broader neuroprotective effect than CS-A,C,K,L. Moreover, sulfation pattern affects not only neuroprotection, but also drug release.

Thermodynamics and Stereochemistry of Diels–Alder Polymer Networks: Role of Crosslinker Flexibility and Crosslinking Density

2021 ◽  
Author(s):  
Qing Zhou ◽  
Zhen Sang ◽  
Kartik Kumar Rajagopalan ◽  
Yelena Sliozberg ◽  
Frank Gardea ◽  
...  
Keyword(s):  
Polymer Networks ◽  
Crosslinking Density ◽  
Diels Alder

ChemInform Abstract: Catalysis and Polymer Networks - The Role of Morphology and Molecular Accessibility.

ChemInform ◽  
2010 ◽  
Vol 33 (10) ◽  
pp. no-no
Author(s):  
B. Corain ◽  
M. Zecca ◽  
K. Jerabek
Keyword(s):  
Polymer Networks
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