Stimuli-responsive anisotropic actuation of melem-formaldehyde polymer

2020 ◽  
Vol 7 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Yang Wang ◽  
Niannian Wu ◽  
Congyan Liu ◽  
Mohamed K. Albolkany ◽  
Min Wang ◽  
...  

The intrinsically anisotropic melem-formaldehyde polymer that is constructed from a self-assembly process enables reversible anisotropic actuation under external stimuli.

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1698
Author(s):  
Athanasios Skandalis ◽  
Theodore Sentoukas ◽  
Despoina Giaouzi ◽  
Martha Kafetzi ◽  
Stergios Pispas

This review article aims to cover the most recent advances regarding the synthesis of linear ABC-type triblock terpolymers and star-shaped polymers by RAFT polymerization, as well as their self-assembly properties in aqueous solutions. RAFT polymerization has received extensive attention, as it is a versatile technique, compatible with a great variety of functional monomers and reaction conditions, while providing exceptional and precise control over the final structure, with well-defined side-groups and post-polymerization engineering potential. Linear triblock terpolymers synthesis can lead to very interesting novel ideas, since there are countless combinations of stimuli/non-stimuli and hydrophilic/hydrophobic monomers that someone can use. One of their most interesting features is their ubiquitous ability to self-assemble in different nanostructures depending on their degree of polymerization (DP), block composition, solubilization protocol, internal and external stimuli. On the other hand, star-shaped polymers exhibit a more stable nanostructure, with a distinct crosslinked core and arm blocks that can also incorporate stimuli-responsive blocks for “smart” applications.


TECHNOLOGY ◽  
2016 ◽  
Vol 04 (04) ◽  
pp. 217-228 ◽  
Author(s):  
Papatya Kaner ◽  
Prity Bengani-Lutz ◽  
Ilin Sadeghi ◽  
Ayse Asatekin

Membrane technologies are essential for water treatment, bioprocessing and chemical manufacturing. Stimuli-responsive membranes respond to changes in feed conditions (e.g., temperature, pH) or external stimuli (e.g., magnetic field, light) with a change in performance parameters (permeability, selectivity). This enables new functionalities such as tunable performance, self-cleaning and smart-valve behavior. Polymer self-assembly is a crucial tool for manufacturing such membranes using scalable methods, enabling easier commercialization. This review surveys approaches to impart stimuli responsive behavior to membrane filters using polymer self-assembly.


2020 ◽  
Vol 11 (17) ◽  
pp. 3003-3017 ◽  
Author(s):  
Xiaomin Zhu ◽  
Jian Zhang ◽  
Cheng Miao ◽  
Siyu Li ◽  
Youliang Zhao

Stimuli-responsive miktobrush-coil terpolymers can exhibit unique physical properties and hierarchical self-assembly behaviors dependent on composition, concentration and external stimuli.


2020 ◽  
Vol 2 (6) ◽  
pp. 2525-2530
Author(s):  
Javier Reguera ◽  
Tatjana Flora ◽  
Naomi Winckelmans ◽  
José C. Rodríguez-Cabello ◽  
Sara Bals

Novel suprastructures, from small clusters to micelle-like structures, are obtained by self-assembly of Janus Au:Fe3O4 nanostars under external stimuli.


2021 ◽  
Author(s):  
Yuxuan Zhang ◽  
Jie Huang ◽  
Jun Zhang ◽  
Xinyuan Zhu ◽  
Gangsheng Tong

Stimuli-responsive polypeptoids are promising peptidomimetic polymers that can regulate their physical/chemical properties by means of external stimuli and have been drawn tremendous attention for potential biotechnological applications. Here, we report...


Author(s):  
Gore S. A. ◽  
Gholve S. B. ◽  
Savalsure S. M. ◽  
Ghodake K. B. ◽  
Bhusnure O. G. ◽  
...  

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.


Author(s):  
Krishna Sailaja A ◽  
Amareshwar P

In order to see the functionality and toxicity of nanoparticles in various food and drug applications, it is important to establish procedures to prepare nanoparticles of a controlled size. Desolvation is a thermodynamically driven self-assembly process for polymeric materials. In this study, we prepared BSA nanoparticles using the desolvation technique using acetone as desolvating agent. Acetone was added intermittently into 1% BSA solution at different pH under stirring at 700 rpm. Amount of acetone added, intermittent timeline of acetone addition, and pH of solution were considered as process parameters to be optimized. The effect of the process parameters on size of the nanoparticles was studied. The results indicated that the size control of BSA nanoparticles was achieved by adding acetone intermittently. The standard deviation of average size of BSA nanoparticles at each preparation condition was minimized by adding acetone intermittently. The intermittent addition in polymeric aqueous solution can be useful for size control for food or drug applications.  


2019 ◽  
Vol 4 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Ryan T. Shafranek ◽  
Joel D. Leger ◽  
Song Zhang ◽  
Munira Khalil ◽  
Xiaodan Gu ◽  
...  

Directed self-assembly in polymeric hydrogels allows tunability of thermal response and viscoelastic properties.


Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 114
Author(s):  
Chang Lu ◽  
Qingjian Lu ◽  
Min Gao ◽  
Yuan Lin

The reversible and multi-stimuli responsive insulator-metal transition of VO2, which enables dynamic modulation over the terahertz (THz) regime, has attracted plenty of attention for its potential applications in versatile active THz devices. Moreover, the investigation into the growth mechanism of VO2 films has led to improved film processing, more capable modulation and enhanced device compatibility into diverse THz applications. THz devices with VO2 as the key components exhibit remarkable response to external stimuli, which is not only applicable in THz modulators but also in rewritable optical memories by virtue of the intrinsic hysteresis behaviour of VO2. Depending on the predesigned device structure, the insulator-metal transition (IMT) of VO2 component can be controlled through thermal, electrical or optical methods. Recent research has paid special attention to the ultrafast modulation phenomenon observed in the photoinduced IMT, enabled by an intense femtosecond laser (fs laser) which supports “quasi-simultaneous” IMT within 1 ps. This progress report reviews the current state of the field, focusing on the material nature that gives rise to the modulation-allowed IMT for THz applications. An overview is presented of numerous IMT stimuli approaches with special emphasis on the underlying physical mechanisms. Subsequently, active manipulation of THz waves through pure VO2 film and VO2 hybrid metamaterials is surveyed, highlighting that VO2 can provide active modulation for a wide variety of applications. Finally, the common characteristics and future development directions of VO2-based tuneable THz devices are discussed.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.


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