scholarly journals Nano- and microgels: a review for educators

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Denis M. Zhilin ◽  
Andrij Pich
Keyword(s):  
Drug Delivery ◽  
Building Blocks ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Soft Polymer ◽  
Application Fields ◽  
Learning Projects

Abstract Nano- and microgels are promising soft polymer materials for different application fields: stabilizers, sensors, catalysts, selective sorbents, drug delivery carriers etc. They are composed of cross-linked polymer chains swollen with a solvent. The building blocks, synthesis approaches and architecture of nano- and microgels are reviewed. The mechanisms of responsiveness to various stimuli are described, examples of applications are provided. Micro- and nanogels are good objects for learning projects and the ideas for learning projects with microgels are described.

scholarly journals Recent Advances of the Polymer Micro/Nanofiber Fluorescence Waveguide

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1086 ◽  
Author(s):  
Hongyan Xia ◽  
Tingkuo Chen ◽  
Chang Hu ◽  
Kang Xie
Keyword(s):  
Optical Waveguide ◽  
High Performance ◽  
Building Blocks ◽  
Transmission Efficiency ◽  
Photonic Devices ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Optical Wave ◽  
Integrated Optical ◽  
Photonic Components

Subwavelength optical micro/nanofibers have several advantages, such as compact optical wave field and large specific surface area, which make them widely used as basic building blocks in the field of micro-nano optical waveguide and photonic devices. Among them, polymer micro/nanofibers are among the first choices for constructing micro-nano photonic components and miniaturized integrated optical paths, as they have good mechanical properties and tunable photonic properties. At the same time, the structures of polymer chains, aggregated structures, and artificial microstructures all have unique effects on photons. These waveguided micro/nanofibers can be made up of not only luminescent conjugated polymers, but also nonluminous matrix polymers doped with luminescent dyes (organic and inorganic luminescent particles, etc.) due to the outstanding compatibility of polymers. This paper summarizes the recent progress of the light-propagated mechanism, novel design, controllable fabrication, optical modulation, high performance, and wide applications of the polymer micro/nanofiber fluorescence waveguide. The focus is on the methods for simplifying the preparation process and modulating the waveguided photon parameters. In addition, developing new polymer materials for optical transmission and improving transmission efficiency is discussed in detail. It is proposed that the multifunctional heterojunctions based on the arrangement and combination of polymer-waveguided micro/nanofibers would be an important trend toward the construction of more novel and complex photonic devices. It is of great significance to study and optimize the optical waveguide and photonic components of polymer micro/nanofibers for the development of intelligent optical chips and miniaturized integrated optical circuits.

Hydrogels: A Versatile Drug Delivery Carrier Systems

1970 ◽  
Vol 5 (3) ◽  
pp. 1745-1756
Author(s):  
L H Baldaniya ◽  
Sarkhejiya N A
Keyword(s):  
Drug Delivery ◽  
Protein Delivery ◽  
Structural Integrity ◽  
Healing Process ◽  
Polymer Chains ◽  
Wound Healing Process ◽  
Aqueous Environment ◽  
Preparation Methods ◽  
Control Drug

Hydrogels are the material of choice for many applications in regenerative medicine due to their unique properties including biocompatibility, flexible methods of synthesis, range of constituents, and desirable physical characteristics. Hydrogel (also called Aquagel) is a network of polymer chains that are hydrophilic, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are highly absorbent (contain ~99.9% water), natural or synthetic polymers. Hydrogel also possess a degree of flexibility very similar to natural tissue, due to its significant water content. It can serve as scaffolds that provide structural integrity to tissue constructs, control drug and protein delivery to tissues and cultures. Also serve as adhesives or barriers between tissue and material surfaces. The positive effect of hydrogels on wounds and enhanced wound healing process has been proven. Hydrogels provide a warm, moist environment for wound that makes it heal faster in addition to its useful mucoadhesive properties. Moreover, hydrogels can be used as carriers for liposomes containing variety of drugs, such as antimicrobial drugs. Hydrogels are water swollen polymer matrices, with a tendency to imbibe water when placed in aqueous environment. This ability to swell, under biological conditions, makes it an ideal material for use in drug delivery and immobilization of proteins, peptides, and other biological compounds. Hydrogels have been extensively investigated for use as constructs to engineer tissues in vitro. This review describes the properties, classification, preparation methods, applications, various monomer used in formulation and development of hydrogel products.

scholarly journals Soft Jumping Robot Using Soft Morphing and the Yield Point of Magnetic Force

2021 ◽  
Vol 11 (13) ◽  
pp. 5891
Author(s):  
Gang-Hyun Jeon ◽  
Yong-Jai Park
Keyword(s):  
Residual Stress ◽  
Polymer Materials ◽  
Rigid Base ◽  
Release Mechanism ◽  
Transfer Energy ◽  
Deformation Control ◽  
Energy Retention ◽  
Base Jumping ◽  
Jumping Robot ◽  
Soft Polymer

In this paper, soft-morphing, deformation control by fabric structures and soft-jumping mechanisms using magnetic yield points are studied. The durability and adaptability of existing rigid-base jumping mechanisms are improved by a soft-morphing process that employs the residual stress of a polymer. Although rigid body-based jumping mechanisms are used, they are driven by multiple components and complex structures. Therefore, they have drawbacks in terms of shock durability and fatigue accumulation. To improve these problems, soft-jumping mechanisms are designed using soft polymer materials and soft-morphing techniques with excellent shock resistance and environmental adaptability. To this end, a soft jumping mechanism is designed to store energy using the air pressure inside the structure, and the thickness of the polymer layer is adjusted based on the method applied for controlling the polymer freedom and residual stress deformation. The soft jumping mechanism can transfer energy more efficiently and stably using an energy storage and release mechanism and the rounded ankle structure designed using soft morphing. Therefore, the soft morphing and mechanisms of energy retention and release were applied to fabricate a soft robot prototype that can move in the desired direction and jump; the performance experiment was carried out.

Principles of exposure of polymer materials to heat, moisture and UV-radiation and study of their properties by full factorial experiment: A review

2021 ◽  
pp. 146-160
Author(s):  
A. B. Laptev ◽  
A. S. Nesterov ◽  
A. M. Vardanyan ◽  
A. M. Vardanyan
Keyword(s):  
Uv Radiation ◽  
Climatic Factors ◽  
Initial Period ◽  
Amorphous State ◽  
Surface Oxidation ◽  
Polymer Chains ◽  
Factorial Experiment ◽  
Polymer Materials ◽  
Full Factorial Experiment ◽  
Full Factorial

The work is dedicated to the effects of climatic factors on polyethylene terephthalate (PET) in terms of changes in the structure and interaction of polymer molecules. The kinetic concept of the strength of PET has been developed, and the factors influencing the strength have been considered. Effects of moisture, thermal oxidative destruction, and UV-radiation on the structure of PET have been investigated. Polymers’ properties predicting, durability and their computer modeling have been analyzed. A model of changes in PET properties under the influence of temperature, moisture and UV-radiation was constructed using the methods of a full factorial experiment. It has been shown that in the initial period of exposure, adsorption and diffusion of moisture, hydrolysis and surface oxidation occur; prolonged and constant exposure to UV-radiation break the bonds formed by moisture, then the C–C and C–O bonds in the PET molecule brake and new intermolecular bonds are formed. In the amorphous state of PET, the breaking of bonds in the polymer chain and the formation of bonds between two adjacent polymer chains, the formation of more densely packed nodes, the destruction of the polymer and its aging, are equally probable. Temperature has a secondary effect, facilitating both hydrolysis and oxidation and polymer degradation.

scholarly journals STRUCTURAL AND MECHANICAL CHARACTERIZATION OF DEFORMED POLYMER USING CONFOCAL RAMAN MICROSCOPY AND DSC

2016 ◽  
Vol 3 ◽  
pp. 47-50
Author(s):  
Birgit Neitzel ◽  
Florian Aschermayer ◽  
Milan Kracalik ◽  
Sabine Hild
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Mechanical Characterization ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Confocal Raman Microscopy ◽  
Micro Structure ◽  
Scanning Calorimetry ◽  
Confocal Raman

Polymers have various interesting properties, which depend largely on their inner structure. One way to influence the macroscopic behaviour is the deformation of the polymer chains, which effects the change in microstructure. For analyzing the microstructure of non-deformed and deformed polymer materials, Raman spectroscopy as well as differential scanning calorimetry (DSC) were used. In the present study we compare the results for crystallinity measurements of deformed polymers using both methods in order to characterize the differences in micro-structure due to deformation. The study is ongoing, and we present the results of the first tests.

scholarly journals High-Velocity Shear and Soft Friction at the Nanometer Scale

2021 ◽  
Vol 7 ◽  
Author(s):  
Per-Anders Thorén ◽  
Riccardo Borgani ◽  
Daniel Forchheimer ◽  
David B. Haviland
Keyword(s):  
High Speed ◽  
Surface Deformation ◽  
Soft Materials ◽  
Lateral Force ◽  
Velocity Shear ◽  
Polymer Materials ◽  
Amplitude Dependence ◽  
Dynamic Force ◽  
Stick Slip ◽  
Soft Polymer

We study high-speed friction on soft polymer materials by measuring the amplitude dependence of cyclic lateral forces on the atomic force microscope (AFM) tip as it slides on the surface with fixed contact force. The resulting dynamic force quadrature curves separate the elastic and viscous contributions to the lateral force, revealing a transition from stick-slip to free-sliding motion as the velocity increases. We explain force quadratures and describe how they are measured, and we show results for a variety of soft materials. The results differ substantially from the measurements on hard materials, showing hysteresis in the force quadrature curves that we attribute to the finite relaxation time of viscoelastic surface deformation.

Effects of Co-Solvents on Loading and Release Properties of Self-Assembled Di-Peptide Building Blocks, towards Drug Delivery Applications

2021 ◽  
Vol 28 ◽  
Author(s):  
Sara Yazdani ◽  
Seyed Mohammad Ghoreishi ◽  
Neda Habibi
Keyword(s):  
Drug Delivery ◽  
Building Blocks ◽  
Amino Acid Sequences ◽  
Molecular Structures ◽  
Flufenamic Acid ◽  
Mixture Ratio ◽  
Drug Molecules ◽  
Release Capacity ◽  
Essential Properties ◽  
Drug Delivery Applications

Background: Due to their solid-like porous structure, molecular organogel and microcrystal structures have the capabilities of loading drug molecules, encapsulation, and extended release, all considered as essential properties in drug delivery applications. Phases of these structures, however, depend on the solvent used during the gelation process. Objective: Understanding the phase transition between organogel and microcrystal structures through adjusting the mixture ratio of different co-solvents. Method: Short peptide Diphenylalanine as the gelation building block was used due to its amino acid sequences that can be exactly selected at its molecular levels. Ethanol as a polar solvent was used in combination with four other co-solvents with different polarity levels, namely Xylene, Toluene, Acetone, and Dimethyl Sulfoxide. The morphology of molecular structures of each co-solvent combination at each ratio level was examined as well as the loading and release properties for a non-polar Flufenamic Acid drug. Results: The resultant structure wasaffected by the polarity of the co-solvents; in particular, in the sample containing 25 μg/ml of the drug, 94% of the drug amount was loaded inside the organogel. By increasing the drug concentration to 50, 75, and 100 μg/ml, the loading capability decreased to 76%, 47%, and 33%, respectively. Conclusion: Molecular organogels have excellent capabilities of loading drug molecules, while microcrystal structures have higher release capacity. The findings of this study reveal how to best design a gelation method to obtain maximum loading or release properties for a particular peptide-based drug delivery application.

scholarly journals Influence of the Architecture of Soft Polymer-Functionalized Polymer Nanoparticles on Their Dynamics in Suspension

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1844
Author(s):  
Young-Gon Kim ◽  
Waraporn Wichaita ◽  
Héloïse Thérien-Aubin
Keyword(s):  
Correlation Time ◽  
Nmr Relaxation ◽  
Thick Layer ◽  
Polymer Chains ◽  
The Core ◽  
Grafting Density ◽  
Tethered Polymer Chains ◽  
Close Proximity ◽  
Soft Polymer ◽  
Tethered Chains

The behavior of nanogels in suspension can be dramatically affected by the grafting of a canopy of end-tethered polymer chains. The architecture of the interfacial layer, defined by the grafting density and length of the polymer chains, is a crucial parameter in defining the conformation and influencing the dynamics of the grafted chains. However, the influence of this architecture when the core substrate is itself soft and mobile is complex; the dynamics of the core influences the dynamics of the tethered chains, and, conversely, the dynamics of the tethered chains can influence the dynamics of the core. Here, poly(styrene) (PS) particles were functionalized with poly(methyl acrylate) (PMA) chains and swollen in a common solvent. NMR relaxation reveals that the confinement influences the mobility of the grafted chain more prominently for densely grafted short chains. The correlation time associated with the relaxation of the PMA increased by more than 20% when the grafting density increased for short chains, but for less than 10% for long chains. This phenomenon is likely due to the steric hindrance created by the close proximity to the rigid core and of the neighboring chains. More interestingly, a thick layer of a densely grafted PMA canopy efficiently increases the local mobility of the PS cores, with a reduction of the correlation time of more than 30%. These results suggest an interplay between the dynamics of the core and the dynamics of the canopy.

scholarly journals Stealth Coating of Nanoparticles in Drug-Delivery Systems

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 787 ◽  
Author(s):  
See Yee Fam ◽  
Chin Fei Chee ◽  
Chean Yeah Yong ◽  
Kok Lian Ho ◽  
Abdul Razak Mariatulqabtiah ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Blood Circulation ◽  
Delivery Systems ◽  
Mononuclear Phagocyte ◽  
Polymer Chains ◽  
Cancer Therapies ◽  
Drug Actions ◽  
Coating Characteristics ◽  
Systemic Side Effects ◽  
Poly Ethylene

Nanoparticles (NPs) have emerged as a powerful drug-delivery tool for cancer therapies to enhance the specificity of drug actions, while reducing the systemic side effects. Nonetheless, NPs interact massively with the surrounding physiological environments including plasma proteins upon administration into the bloodstream. Consequently, they are rapidly cleared from the blood circulation by the mononuclear phagocyte system (MPS) or complement system, resulting in a premature elimination that will cause the drug release at off-target sites. By grafting a stealth coating layer onto the surface of NPs, the blood circulation half-life of nanomaterials can be improved by escaping the recognition and clearance of the immune system. This review focuses on the basic concept underlying the stealth behavior of NPs by polymer coating, whereby the fundamental surface coating characteristics such as molecular weight, surface chain density as well as conformations of polymer chains are of utmost importance for efficient protection of NPs. In addition, the most commonly used stealth polymers such as poly(ethylene glycol) (PEG), poly(2-oxazoline) (POx), and poly(zwitterions) in developing long-circulating NPs for drug delivery are also thoroughly discussed. The biomimetic strategies, including the cell-membrane camouflaging technique and CD47 functionalization for the development of stealth nano-delivery systems, are highlighted in this review as well.

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