Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Preparation of Organosiloxane Telechelics by Cationic Ring-Opening Polymerization
Polydimethylsiloxanes (PDMS) telechelics are important both in industry and in academic research. They are used both in the free state and as part of copolymers and cross-linked materials. The most important, practically used, and well-studied method for the preparation of such PDMS is diorganosiloxane ring-opening polymerization (ROP) in the presence of nucleophilic or electrophilic initiators. Cationic ROP is also of interest for the preparation of functional PDMS. The advantage of this process is that it can be carried out at a relatively low temperature, the catalyst can be easily deactivated, and the process can also be used to synthesize polysiloxanes having base-sensitive substituents such as Si–H or Si–(CH2)3–SH.
  • 641
  • 24 Jun 2022
Topic Review
Fully Implanted Hearing Systems
The ear and brain work together in the hearing process. Sound energy in the audible frequency range (20 Hz–20 kHz) propagates through air medium as an acoustical mechanical wave which enters from the outer ear towards the middle ear to vibrate the eardrum. 
  • 637
  • 02 Aug 2021
Topic Review
Properties and Bioactivity of Chitosan
Chitosan (CS) is a natural biopolymer derived by deacetylation (N-acetyl-D-glucosamine to D-glucosamine unit) of chitin.
  • 636
  • 11 Jun 2021
Topic Review
Types of Micellar Assemblies
Amphiphilic block copolymers (with a variety of hydrophobic blocks and hydrophilic blocks; often polyethylene oxide) self-assemble in water to micelles/niosomes similar to conventional nonionic surfactants with high drug loading capacity.
  • 636
  • 08 Nov 2022
Topic Review
Directed Assembly of Particle-Polymer Composites
Particle-polymer dispersions are ubiquitous in additive manufacturing (AM), where they are used as inks to create composite materials with applications to wearable sensors, energy storage materials, and actuation elements. It has been observed that directional alignment of the particle phase in the polymer dispersion can imbue the resulting composite material with enhanced mechanical, electrical, thermal or optical properties. 
  • 635
  • 17 Aug 2021
Topic Review
Design and Synthesis of Polyphosphodiesters
Polyacids containing –P(O)(OH)– fragment in the polymer backbone, or polyphosphodiesters (PPDEs), hold a special place among natural and synthetic polymers. The structural similarity of PPDEs to natural nucleic and teichoic acids, biocompatibility of PPDEs and their mimicking to biomolecules providing the ‘stealth effect’, high bone mineral affinity of PPDEs, and adjustable hydrolytic stability of PPDEs are the basis for various biomedical, industrial and household applications. Actual synthetic approaches to PPDEs are based on incredibly rich chemistry of organic phosphates and phosphonates, and include modern techniques such as catalytic ring-opening polymerization (ROP), acyclic diene metathesis (ADMET) polycondensation, and others.
  • 632
  • 09 Jan 2023
Topic Review
Membrane-Based Environmental Remediation
During the last century, industrialization has grown very fast and as a result heavy metals have contaminated many water sources. Due to their high toxicity, these pollutants are hazardous for humans, fish, and aquatic flora. Traditional techniques for their removal are adsorption, electro-dialysis, precipitation, and ion exchange, but they all present various drawbacks. Membrane technology represents an exciting alternative to the traditional ones characterized by high efficiency, low energy consumption and waste production, mild operating conditions, and easy scale-up. In this review, the attention has been focused on applying driven-pressure membrane processes for heavy metal removal, highlighting each of the positive and negative aspects. Advantages and disadvantages, and recent progress on the production of nanocomposite membranes and electrospun nanofiber membranes for the adsorption of heavy metal ions have also been reported and critically discussed. Finally, future prospective research activities and the key steps required to make their use effective on an industrial scale have been presented
  • 630
  • 02 Jul 2021
Topic Review
Fabrication-4D-Printed Shape Memory Polymers
Additive manufacturing (AM) is the process through which components/structures are produced layer-by-layer. In this context, 4D printing combines 3D printing with time so that this combination results in additively manufactured components that respond to external stimuli and, consequently, change their shape/volume or modify their mechanical properties. Therefore, 4D printing uses shape-memory materials that react to external stimuli such as pH, humidity, and temperature. Among the possible materials with shape memory effect (SME), the most suitable for additive manufacturing are shape memory polymers (SMPs).
  • 627
  • 27 Apr 2021
Topic Review
ABC-Type Linear Triblock Terpolymers
This entry aims to cover the most recent advances regarding the synthesis of linear ABC-type triblock terpolymers 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. 
  • 625
  • 26 May 2021
Topic Review
Sulfonimide-Based Dendrimers
Dendrimers are multifunctional polymer compounds with a tree-like shape and a high branching degree. 
  • 623
  • 25 Feb 2021
  • Page
  • of
  • 46
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback