Growth of wormlike micelles of surfactant induced by embedded polymer: role of polymer chain length

Soft Matter ◽  
2018 ◽  
Vol 14 (23) ◽  
pp. 4792-4804 ◽  
Author(s):  
Alexander L. Kwiatkowski ◽  
Vyacheslav S. Molchanov ◽  
Hari Sharma ◽  
Alexander I. Kuklin ◽  
Elena E. Dormidontova ◽  
...  
Keyword(s):  
Chain Length ◽  
Polymer Chain ◽  
Polymer Chains ◽  
Wormlike Micelles ◽  
Surfactant Micelles

Long polymer chains embedded in wormlike surfactant micelles can act as crosslinks connecting neighboring micelles.

PHOTOLYSIS OF POLYMETHACRYLIC ACID IN AQUEOUS SOLUTIONS

1964 ◽  
Vol 42 (3) ◽  
pp. 522-531 ◽  
Author(s):  
C. H. Chou ◽  
H. H. G. Jellinek
Keyword(s):  
Aqueous Solutions ◽  
Chain Length ◽  
Polymer Chain ◽  
Irradiation Time ◽  
Polymer Concentration ◽  
Chain Scission ◽  
Polymer Chains ◽  
Polymethacrylic Acid ◽  
Degree Of Ionization ◽  
Ph Values

The photolysis of polymethacrylic acid was studied in aqueous solutions as a function of pH, polymer concentration, polymer chain length, and small additions of electrolytes in the absence of oxygen with light of wavelength 2537 Å. The random chain scission constants decrease with increasing pH values. Small variations in polymer chain length and concentration and electrolyte concentration have no effect on the photolysis. Changes in the ultraviolet spectra with irradiation time are more pronounced at low pH values than higher ones. It is shown that the decrease in susceptibility to photolysis with increasing degree of ionization of the acid is not proportional to the decrease or increase of the number of COOH or COO− groups respectively. It is rather due to the same causes—that is changes in ionic atmosphere— which make the polymer chains uncoil with increasing ionization.

Translocation of polymer chain in post array induced by arrangement differ

2017 ◽  
Vol 31 (04) ◽  
pp. 1750028 ◽  
Author(s):  
Ji-Xuan Hou ◽  
Ye-Hui Zhang ◽  
Yao Chen ◽  
Xu-Chen Yu
Keyword(s):  
Chain Length ◽  
Polymer Chain ◽  
Energy Difference ◽  
Boltzmann Distribution ◽  
Polymer Chains ◽  
Monte Carlo Algorithm ◽  
Entropic Force ◽  
Free Energy Difference ◽  
Directional Preference ◽  
Post Array

We demonstrate that the arrangement differs of posts have significant effect on the translocation of polymer chains which are embedded in the post arrays by using Monte Carlo algorithm. Due to the equivalent entropic force, polymers have a tendency to translocate to the disordered-arranged post array side other than the ordered-arranged side even though the post densities are equal on both sides. By changing the diameter of the posts, we find that the associated translocation times are strongly affected by the structure of the post array. Since the entropic force is almost identical for each monomer of the polymer chain and the free energy difference between two differently-arranged sides increases linearly with the polymer chain length, the directional preference strongly depends on the polymer chain length, and the ratio between the probabilities for a polymer to move either side obeys the Boltzmann distribution. Hence, a new microfabricated device which is used to separate deoxyribonucleic acid (DNA) by molecular weight can be designed using this idea. Moreover, this study can help us to develop a better understanding on the passages of polymers across membranes in nature.

scholarly journals Influence of lactide vs glycolide composition of poly (lactic-co-glycolic acid) polymers on encapsulation of hydrophobic molecules: molecular dynamics and formulation studies

2021 ◽  
Vol 32 (10) ◽  
Author(s):  
Anurag Dobhal ◽  
Ashu Srivastav ◽  
Prajakta Dandekar ◽  
Ratnesh Jain
Keyword(s):  
Molecular Dynamics ◽  
Chain Length ◽  
Polymer Chain ◽  
Continuous Process ◽  
Spatial Arrangement ◽  
Binding Energies ◽  
Polymer Chains ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Coumarin 6

AbstractThe work demonstrates the preparation of PLGA (PLGA 50:50, PLGA 75:25) nanoparticles, to encapsulate a hydrophobic molecule (coumarin-6), using the microreactor-based continuous process. The formulations were characterized using dynamic light scattering and transmission electron microscopy to determine their size, homogeneity, zeta potential, and surface morphology. The resulting nanoparticles were safe to the CHO cells (≈80% cell survival), at the concentration of ≤600 µg/mL and were successfully taken up by the cells, as demonstrated using confocal microscopy. Moreover, imaging flow cytometry confirmed that the nanoparticles were internalized in 73.96% of the cells. Furthermore, molecular dynamics simulation and docking studies were carried out to explore the effect of polymer chain length of PLGA and lactide vs glycolide (LA:GA) ratio on their compatibility with the coumarin-6 molecules and to study the coiling and flexibility of PLGA in the presence of coumarin-6 molecules. Flory–Huggins interaction parameter (χ) was calculated for polymer chains of varying lengths and LA:GA ratio, with respect to coumarin-6. χ parameter increased with increase in polymer chain length, which indicated superior interaction of coumarin-6 with the smaller chains. Amongst all the polymeric systems, PLGA55 exhibited the strongest interaction with coumarin-6, for all the chain lengths, possibly because of their homogeneous spatial arrangements and superior binding energy. PLGA27 showed better compatibility compared to PLGA72 and PGA, whereas PLA-based polymers exhibited the least compatibility. Analysis of the radius of gyration of the polymer chains in the polymer–coumarin-6 complexes, at the end of molecular dynamics run, exhibited that the polymer chains displayed varying coiling behavior and flexibility, depending upon the relative concentrations of the polymer and coumarin-6. Factors like intra-chain interactions, spatial arrangement, inter-chain binding energies, and polymer–coumarin-6 compatibility also influenced the coiling and flexibility of polymer chains.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

scholarly journals Transcriptome Changes in Pseudomonas putida KT2440 during Medium-Chain-Length Polyhydroxyalkanoate Synthesis Induced by Nitrogen Limitation

2020 ◽  
Vol 22 (1) ◽  
pp. 152
Author(s):  
Dorota Dabrowska ◽  
Justyna Mozejko-Ciesielska ◽  
Tomasz Pokój ◽  
Slawomir Ciesielski
Keyword(s):  
Chain Length ◽  
Nitrogen Limitation ◽  
Stringent Response ◽  
Wild Type ◽  
Pseudomonas Putida Kt2440 ◽  
Medium Chain ◽  
Environmental Stimuli ◽  
Medium Chain Length ◽  
In The Wild

Pseudomonas putida’s versatility and metabolic flexibility make it an ideal biotechnological platform for producing valuable chemicals, such as medium-chain-length polyhydroxyalkanoates (mcl-PHAs), which are considered the next generation bioplastics. This bacterium responds to environmental stimuli by rearranging its metabolism to improve its fitness and increase its chances of survival in harsh environments. Mcl-PHAs play an important role in central metabolism, serving as a reservoir of carbon and energy. Due to the complexity of mcl-PHAs’ metabolism, the manner in which P. putida changes its transcriptome to favor mcl-PHA synthesis in response to environmental stimuli remains unclear. Therefore, our objective was to investigate how the P. putida KT2440 wild type and mutants adjust their transcriptomes to synthesize mcl-PHAs in response to nitrogen limitation when supplied with sodium gluconate as an external carbon source. We found that, under nitrogen limitation, mcl-PHA accumulation is significantly lower in the mutant deficient in the stringent response than in the wild type or the rpoN mutant. Transcriptome analysis revealed that, under N-limiting conditions, 24 genes were downregulated and 21 were upregulated that were common to all three strains. Additionally, potential regulators of these genes were identified: the global anaerobic regulator (Anr, consisting of FnrA, Fnrb, and FnrC), NorR, NasT, the sigma54-dependent transcriptional regulator, and the dual component NtrB/NtrC regulator all appear to play important roles in transcriptome rearrangement under N-limiting conditions. The role of these regulators in mcl-PHA synthesis is discussed.

Effect of surface properties and polymer chain length on polymer adsorption in solution

2021 ◽  
Vol 155 (3) ◽  
pp. 034701
Author(s):  
Emily Y. Lin ◽  
Amalie L. Frischknecht ◽  
Karen I. Winey ◽  
Robert A. Riggleman
Keyword(s):  
Surface Properties ◽  
Chain Length ◽  
Polymer Chain ◽  
Polymer Adsorption ◽  
Effect Of Surface

Effect of Polymer Chain Length on the Superlattice Assembly of Functionalized Gold Nanoparticles

Langmuir ◽  
2021 ◽  
Author(s):  
Hyeong Jin Kim ◽  
Wenjie Wang ◽  
Honghu Zhang ◽  
Guillaume Freychet ◽  
Benjamin M. Ocko ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Chain Length ◽  
Polymer Chain ◽  
Functionalized Gold Nanoparticles

scholarly journals Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1636
Author(s):  
Stella Afroditi Mountaki ◽  
Maria Kaliva ◽  
Konstantinos Loukelis ◽  
Maria Chatzinikolaidou ◽  
Maria Vamvakaki
Keyword(s):  
Carboxylic Acid ◽  
Chain Length ◽  
Main Chain ◽  
Alkyl Chain ◽  
Click Reaction ◽  
Irradiation Time ◽  
Alkyl Chain Length ◽  
Polymer Chains ◽  
Condensation Polymerization ◽  
L929 Fibroblast

Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.

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