Tough strained fibers of a polyelectrolyte complex: pretensioned polymers

RSC Advances ◽  
2014 ◽  
Vol 4 (87) ◽  
pp. 46675-46679 ◽  
Author(s):  
Qifeng Wang ◽  
Joseph B. Schlenoff
Keyword(s):  
Shape Memory ◽  
Polyelectrolyte Complex ◽  
Hot Water ◽  
Polyelectrolyte Complexes ◽  
Highly Strained

Polyelectrolyte complexes, long considered “unprocessible”, are transformed from brittle to tough by extrusion into highly strained fibers with a salt/temperature equivalence relaxation and efficient shape memory in hot water.

Preparation and Characterization of Chitosan/Alginate Polyelectrolyte Complex Prepared by Using Calcium Tripolyphosphate Ionic Gelator

2016 ◽  
Vol 857 ◽  
pp. 447-451
Author(s):  
Nur Syairah Muhamad Rahim ◽  
Norlaily Ahmad ◽  
Dzaraini Kamarun
Keyword(s):  
Single Molecule ◽  
Polyelectrolyte Complex ◽  
Sodium Tripolyphosphate ◽  
Hybrid Compound ◽  
Polyelectrolyte Complexes ◽  
Sem Image ◽  
Degradation Temperature ◽  
Prepared Material ◽  
True Hybrid ◽  
The Individual

The formation of polyelectrolyte complexes (PECs) between chitosan and alginate has been widely investigated for many pharmaceutical and biomedical uses. Ionotropic gelation resulted from the crosslinking of polyelectrolytes (PEs) in the presence of ionic crosslinkers to form hydrogels. The most widely used ionic crosslinker for chitosan is sodium tripolyphosphate (NaTPP); and Ca2+ ions for alginates. The use of these cross-linkers to prepare PECs of chitosan and alginates resulted in hydrogels of similar moieties: chitosan-chitosan and alginate-alginate rather than the sought for hybrid chitosan-alginate PECs. Calcium tripolyphosphate (CaTPP) is a single molecule ionic gelator of chitosan and alginate that have the capability of producing the true hybrid compound of chitosan/alginate polyelectrolyte complex. This paper reported the synthesis of calcium tripolyphosphate and the preparation of a hybrid chitosan/alginate PECs using this newly identified ionic gelator. The newly-synthesized ionic gelator was characterized using ICP-OES; the PECs thereof prepared were characterized using TGA and SEM. The degradation temperature of the prepared PECs is higher than the degradation temperatures of the individual chitosan and alginates. SEM image of the prepared PECs showed rougher surfaces compared to the images of the individual chitosan and alginate compound. Both TGA and SEM revealed the possibility of the newly prepared material to be of the PECs sought for.

Tuning the antifouling property of PVDF ultrafiltration membrane with surface anchored polyelectrolyte complexes for sewage treatment

RSC Advances ◽  
2015 ◽  
Vol 5 (78) ◽  
pp. 63580-63587 ◽  
Author(s):  
Xinzhen Zhao ◽  
Aiwen Qin ◽  
Dapeng Liu ◽  
Chunju He
Keyword(s):  
Polyelectrolyte Complex ◽  
Sewage Treatment ◽  
Ultrafiltration Membrane ◽  
Polyelectrolyte Complexes ◽  
Pvdf Membrane ◽  
Antifouling Property

Surface anchored polyelectrolyte complex significantly improved the antifouling performance of PVDF membrane.

Comparative analysis of electrical and hot water actuation of shape memory alloy spring using thermo-mechanical cycle test bench

2016 ◽  
Vol 67 (1) ◽  
pp. 100 ◽  
Author(s):  
Tameshwar Nath ◽  
Priya Chouhan ◽  
Reena Disawal ◽  
I.A. Palani
Keyword(s):  
Energy Source ◽  
Comparative Analysis ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Smart Materials ◽  
Thermo Gravimetric Analysis ◽  
Industrial Applications ◽  
Hot Water ◽  
Gravimetric Analysis ◽  
High Oxygen Content

<p>The optimal design and analysis of hot water actuated shape memory alloy spring is presented. Smart materials exhibit special properties that make them a preferred choice for industrial applications in many branches of engineering. The serviceable properties of a Ni-Ti piece can be improved by altering the energy source. With hot water actuation, as the temperature reaches 70 °C - 90 °C, spring gets fully compressed for the first few cycles followed by loss in actuation. The actuation loss is then studied with different characterisation methods such as thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). With SEM results, it can be strongly recommended that the energy source is sufficient for actuation (not affecting too much the structure). Results observed from TGA shows high oxygen content at lower temperature, suggest the need of conducting experiments in inert atmosphere. For the validation of hot water actuation, comparative analysis between electrical and hot water actuation is done. Graph shows that, there is a good agreement between both the methods. In addition to this, the application of hot water actuation is some micro-devices like micro-valve, drug delivery, directional control valve, also in engine in place of thermostat valve etc.</p>

Shape Recovery Characteristics of 3D Printed Soft Polymers and Their Composites

2016 ◽  
Author(s):  
Wenbo Liu ◽  
Nan Wu ◽  
Kishore Pochiraju
Keyword(s):  
High Resolution ◽  
Shape Memory ◽  
Recovery Time ◽  
Shape Recovery ◽  
Recovery Process ◽  
Hot Water ◽  
Recovery Ratio ◽  
3D Printed ◽  
Term Creep

Shape memory polymers can be triggered to assume memorized shapes from temporarily deformed forms using thermal stimuli. This paper focuses on the characterization of the shape memory behaviors observed in selected 3D printable photo-cured polymer parts and filament with specified fillers. The shape recovery ratio and recovery time were analyzed using 3D printed specimens with 90° bends. Parts with the mixture of selected commercially available polymers — a rigid polymer (RP) and two digitally mixed polymer blends (DB-A and DB-B) were 3D-printed on a multi-material 3D printer capable of producing digital materials with variable mix ratios. The recovery ratios were determined after thermal triggering and after long-term creep (self-recovery) without thermal triggering. The 3D printed parts were heated to above their glass transaction temperature to train temporary shapes and the recovery of original shapes after a thermal trigger was monitored using a high-resolution camera. Long-term self-recovery (non-triggered) was also studied by observing the parts after temporary shape has been trained, as the try to regain their original shape over several days of slow recovery. The recovery of bending angles was quantitatively recorded from the images taken during the shape recovery process. The recovery due to thermal triggers was monitored under a high resolution microscope by reheating with hot water at 90°C. Experiments of long-term self-recovery at room temperature included monitoring of several parts by taking periodic images of the specimens using a resolution camera. The effect of inclusion of fillers on the shape recovery characteristics was also investigated. Silicon Carbide (SiC) with different weight fractions were mixed into PLA powders. Continuous filaments were extruded using a single screw extruder. The recovery time of thermal activation recovery was then characterized to determine the effect of addition of the fillers. The effect of material-mix ratio, initial printed orientation, filler type on the recovery ratio and recovery time are described in this paper.

scholarly journals Hyaluronan/Diethylaminoethyl Chitosan Polyelectrolyte Complexes as Carriers for Improved Colistin Delivery

2021 ◽  
Vol 22 (16) ◽  
pp. 8381
Author(s):  
Natallia V. Dubashynskaya ◽  
Sergei V. Raik ◽  
Yaroslav A. Dubrovskii ◽  
Elena V. Demyanova ◽  
Elena S. Shcherbakova ◽  
...  
Keyword(s):  
Delivery System ◽  
Polyelectrolyte Complex ◽  
Multidrug Resistant ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Polyelectrolyte Complexes ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Positively Charged

Improving the therapeutic characteristics of antibiotics is an effective strategy for controlling the growth of multidrug-resistant Gram-negative microorganisms. The purpose of this study was to develop a colistin (CT) delivery system based on hyaluronic acid (HA) and the water-soluble cationic chitosan derivative, diethylaminoethyl chitosan (DEAECS). The CT delivery system was a polyelectrolyte complex (PEC) obtained by interpolymeric interactions between the HA polyanion and the DEAECS polycation, with simultaneous inclusion of positively charged CT molecules into the resulting complex. The developed PEC had a hydrodynamic diameter of 210–250 nm and a negative surface charge (ζ-potential = −19 mV); the encapsulation and loading efficiencies were 100 and 16.7%, respectively. The developed CT delivery systems were characterized by modified release (30–40% and 85–90% of CT released in 15 and 60 min, respectively) compared to pure CT (100% CT released in 15 min). In vitro experiments showed that the encapsulation of CT in polysaccharide carriers did not reduce its antimicrobial activity, as the minimum inhibitory concentrations against Pseudomonas aeruginosa of both encapsulated CT and pure CT were 1 μg/mL.

Complexation of oppositely charged polymer: novel approaches for drug delivery

2021 ◽  
Vol 18 ◽  
Author(s):  
Ritesh Kumar Tiwari ◽  
Lalit Singh ◽  
Vaibhav Rastogi
Keyword(s):  
Drug Delivery ◽  
Polyelectrolyte Complex ◽  
Review Article ◽  
Polyelectrolyte Complexes ◽  
Complex Development ◽  
The Subject ◽  
Novel Approaches ◽  
Oppositely Charged ◽  
Delivery Technology ◽  
Made In

: The polyelectrolyte complexes (PECs) are adaptable definitions shaped by electrostatic interaction between biopolymers with inverse charges. Polyelectrolyte edifices comprise an exceptional class of polymeric mixtures comprising of polyions with inverse charges, which can be charged either cationically or anionically. Significant advancement has been made in the course of recent years towards new medication conveyance frameworks. The subject of broad essential and applied exploration has been on the marvel of interpolymer collaborations and polyelectrolyte complex development. Basically and applied polyelectrolytes raise on the grounds that the advantages of supportability are perceived in the scholarly world and in modern examination settings. Polyelectrolytes are a form of polymer that has endless ionizable practical arrangements. Ionized polyelectrolytes in arrangement can form a complex with oppositely charged particle called a polyelectrolyte complex. The review article emphasizes on PECs and their classification, characterization, as well as a critical analysis of the current research and applicability in drug delivery technology.

Erosion Resistance of TiNi Shape-Memory Alloy to Hot-Water Jet

2002 ◽  
Vol 394-395 ◽  
pp. 353-356
Author(s):  
Li-Bin Niu ◽  
Toshio Sakuma ◽  
Hiroshi Takaku ◽  
H. Kyogoku ◽  
Y. Sakai
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Erosion Resistance ◽  
Water Jet ◽  
Hot Water

Electrostatic Effects of Metronidazole Loaded in Chitosan-Pectin Polyelectrolyte Complexes

2019 ◽  
Vol 819 ◽  
pp. 27-32
Author(s):  
Sucharat Limsitthichaikoon ◽  
Chutima Sinsuebpol
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Suitable Condition ◽  
Entrapment Efficiency ◽  
Amino Groups ◽  
Polyelectrolyte Complexes ◽  
Large Size ◽  
High Entrapment Efficiency

Electrostatic interactions of polymeric charges become one of the important factors to form the polyelectrolyte complexes (PECs). In this work, PECs has successfully created through the interaction between positive charges of chitosan (CS) and negative charges of pectin (PE) based on the effect of pH and pKa of the polymers. The formation of PECs provides small particle size, positive surface charge, and high %entrapment efficiency (%EE) after loaded metronidazole (MTZ). Dropwise addition of PE solution into CS solution was carried out to form PECs. A certain concentration of chitosan and pectin fixed at ratio 3:1 while the pH of both polymers varied as pH 1, 3, 5, and 9. The alterations after forming PECs observed particle size, zeta potential, and turbidity of the solution along with FTIR, DSC, and TAG. Precipitation of PECs solution was found in the fixed pH 5 of PE solution dropwise into pH 7 and 9 CS solution, which referred to the unstable of the PECs system. The pH 1 and 9 of PE and CS obtained the large size which about 600-1200 nm, while zeta potential found a low positive charge of 5.54-11.90 mV. Thus, only the fixed pH 5 of CS solution and pH 3, 5, or 7 of PE solution to form PECs were used to load MTZ. After loaded MTZ, the particle size of the PECs was about 400-500 nm and the zeta potential was about 20-50 mV. Electrostatic interactions resulted from FTIR detected the changes in amino groups of CS and carboxyl groups of PE. Thermal analysis on DSC for determinations of melting points or transition temperatures and TGA to monitor weight loss by heat were confirmed the PECs and MTZ-PECs formation. The pH 5 of PE interacts with pH 5 of CS offered the smallest particle size as 438 nm, zeta potential about 23.5 mV, and the highest percentage of EE as about 50% of the drug-loaded. The pH 5 of PE and CS were the pH-responsive to the pKa, thus, the acidity of the polymers may provide a suitable condition to form the appropriate polyelectrolyte complexes. Keywords: Polyelectrolyte complex, polycation, polyanion, charge density

Adhesion to wet cellulose – Comparing adhesive layer-by-layer assembly to coating polyelectrolyte complex suspensions 2nd ICC 2007, Tokyo, Japan, October 25–29, 2007

Holzforschung ◽  
2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Xianhua Feng ◽  
Dan Zhang ◽  
Robert Pelton
Keyword(s):  
Polyelectrolyte Complex ◽  
Adhesive Layer ◽  
Regenerated Cellulose ◽  
Layer By Layer ◽  
Polyelectrolyte Complexes ◽  
Wet Adhesion ◽  
Cellulose Films ◽  
Regenerated Cellulose Films ◽  
Wafer Surfaces

Abstract Polyelectrolyte complexes are routinely used as adhesives to strengthen fiber-fiber contacts in paper. This work evaluates different approaches to putting the polyelectrolyte complexes into the adhesive joint. Instead of conventional wet paper mechanical testing, a wet cellulose film delamination technique was employed permitting direct comparison of different approaches to applying the polymeric adhesive to the cellulose-cellulose joint. The adhesion strengths of layer-by-layer polyelectrolyte complexes assembled on wet cellulose films and the adhesion strengths of the corresponding polyelectrolyte complex coated on wet cellulose films are compared. The wet adhesion strengths were measured by peel delamination. The polyelectrolyte complexes were based on mixtures of cationic polyvinylamine (PVAm) and anionic carboxymethyl cellulose (CMC). The layer-by-layer assemblies of PVAm and CMC yielded stronger wet adhesion than did coated films of the corresponding colloidal complexes or pure PVAm at the same coverage (mass of polymer/joint area). The role of CMC was to give ionic crosslinks with PVAm which increase the cohesive strength of thick PVAm layers. PVAm gives much stronger wet adhesion to cellulose compared to the oxidized silicon wafer surfaces. It is proposed that imine and aminal bonds can form between the polyamine and hemiacetals in the regenerated cellulose films which cannot form with silica.

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