scholarly journals Sustainable Water Responsive Mechanically Adaptive and Self-Healable Polymer Composites Derived from Biomass

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 726 ◽  
Author(s):  
Pranabesh Sahu ◽  
Anil K. Bhowmick
Keyword(s):  
Cellulose Nanofibrils ◽  
Self Healing ◽  
Stimuli Responsive ◽  
Force Microscopy ◽  
Water Sensitivity ◽  
Atomic Force ◽  
Healing Efficiency ◽  
Average Modulus ◽  
Healing Property ◽  
Adaptive Composites

New synthetic biobased mechanically adaptive composites, responding to water and having self-healing property, were developed. These composites were prepared by introducing plant-based cellulose nanofibrils (CNFs) at 10, 20, and 25% (v/v) concentration into a biobased rubbery poly (myrcene-co-furfuryl methacrylate) (PMF) matrix by solution mixing and subsequent compression molding technique. The reinforcement of CNFs led to an increase in the tensile storage modulus (E’) of the dry composites. Upon exposure to water, water sensitivity and a drastic fall in storage moduli (E’) were observed for the 25% (v/v) CNF composite. A modulus reduction from 1.27 (dry state) to 0.15 MPa (wet state) was observed for this composite. The water-sensitive nature of the composites was also confirmed from the force modulation study in atomic force microscopy (AFM), revealing the average modulus as 82.7 and 32.3 MPa for dry and swollen composites, respectively. Interestingly, the composites also showed thermoreversibility and excellent healing property via Diels-Alder (DA) click chemistry using bismaleimide as a crosslinker, when the scratched samples were heated at 120 °C (rDA) for 10 h and then cooled down to 60 °C (DA) followed by room temperature. The healing efficiency was obtained as about 90% from the AFM 3D height images. Thus, the composites exhibited dual stimuli-responsive behavior as mechanically adaptive water sensitive polymers with water as the stimulus and self-healing polymer using bismaleimide as an external stimulus. Therefore, this study provides guidance and new frontiers to make use of composite materials based on biopolymers for various potential smart and biomedical applications.

Production of Self-Healing PI Polymeric Films with Encapsulated TMPTA in PU Microparticles

2014 ◽  
Vol 548-549 ◽  
pp. 344-348
Author(s):  
Gulzira Tleubayeva ◽  
Bakhtiyar Khudaibergenov ◽  
Rinat Iskakov ◽  
Indira Tleubayeva
Keyword(s):  
Mechanical Damage ◽  
Spherical Shape ◽  
Polymeric Films ◽  
Self Healing ◽  
Polymeric Coatings ◽  
Force Microscopy ◽  
Atomic Force ◽  
Healing Agent ◽  
Healing Property ◽  
Regular Spherical Shape

The ability of polymeric coatings to self-heal from mechanical damage is explored in this paper. Polymeric coatings with self-healing property isoneof the important aspects in science. It can be used in industries such as oil industry (protect against corrosion), mechanical engineering, aircraft, etc. The PU microparticles were synthesized on the basis of PPG and TDI with a method of interfacial polycondensation at the interface water-benzene. Further to study the surface morphology of the microcapsules with healing agent (TMPTA) obtained PU was applied the method of scanning electron and atomic force microscopy. The PU microparticles hollow inside have regular spherical shape with a diameter of 5-10 μm with a dense and smooth polymeric shell. The resulting polyimide – polyurethane (PI – PU) composites have high potential to regenerate damaged surfaces not only on the surface and also in the volume of composite.

Studies of Nanomechanical Properties of Pulsed Laser Deposited NbN films on Si Using Nanoindentation

2012 ◽  
Vol 1424 ◽  
Author(s):  
M. A. Mamun ◽  
A. H. Farha ◽  
Y. Ufuktepe ◽  
H. E. Elsayed-Ali ◽  
A. A. Elmustafa
Keyword(s):  
Thin Films ◽  
Pulsed Laser ◽  
Niobium Nitride ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Pile Up ◽  
Average Modulus

ABSTRACTNanomechanical and structural properties of pulsed laser deposited niobium nitride thin films were investigated using X-ray diffraction, atomic force microscopy, and nanoindentation. NbN film reveals cubic δ-NbN structure with the corresponding diffraction peaks from the (111), (200), and (220) planes. The NbN thin films depict highly granular structure, with a wide range of grain sizes that range from 15-40 nm with an average surface roughness of 6 nm. The average modulus of the film is 420±60 GPa, whereas for the substrate the average modulus is 180 GPa, which is considered higher than the average modulus for Si reported in the literature due to pile-up. The hardness of the film increases from an average of 12 GPa for deep indents (Si substrate) measured using XP CSM and load control (LC) modes to an average of 25 GPa measured using the DCM II head in CSM and LC modules. The average hardness of the Si substrate is 12 GPa.

Preparation of Cellulose Nanofibrils by High-Pressure Homogenizer and Zein Composite Films

2013 ◽  
Vol 829 ◽  
pp. 534-538 ◽  
Author(s):  
Alireza Shakeri ◽  
Sattar Radmanesh
Keyword(s):  
Atomic Force Microscopy ◽  
High Pressure ◽  
Food Packaging ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Average Diameter ◽  
Nanocomposite Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Pressure Homogenizer

Cellulose nanofibrils ( NF ) have several advantages such as biodegradability and safety toward human health. Zein is a biodegradable polymer with potential use in food packaging applications. It appears that polymer nanocomposites are one of the most promising applications of zein films. Cellulose NF were prepared from starting material Microcrystalline cellulose (MCC) by an application of a high-pressure homogenizer at 20,000 psi and treatment consisting of 15 passes. Methods such as atomic force microscopy were used for confirmation of nanoscale size production of cellulose. The average diameter 45 nm were observed. Zeincellulose NF nanocomposite films were prepared by casting ethanol suspensions of Zein with different amounts of cellulose NF in the 0% to 5%wt. The nanocomposites were characterized by using Fourier transform infrared spectroscopy ( FTIR ), Atomic force microscopy ( AFM ) and X-ray diffraction ( XRD ) analysis. From the FTIR spectra the various groups present in the Zein blend were monitored. The homogeneity, morphology and crystallinity of the blends were ascertained from the AFM and XRD data, respectively. The thermal resistant of the zein nanocomposite films improved as the nanocellulose content increased. These obtained materials are transparent, flexible and present significantly better physical properties than the corresponding unfilled Zein films.

scholarly journals Cellulose-Cyclodextrin Co-Polymer for the Removal of Cyanotoxins on Water Sources

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2075
Author(s):  
Diego Gomez-Maldonado ◽  
Iris Beatriz Vega Erramuspe ◽  
Ilari Filpponen ◽  
Leena-Sisko Johansson ◽  
Salvatore Lombardo ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cellulose Nanofibrils ◽  
Human Consumption ◽  
Nutrient Runoff ◽  
Force Microscopy ◽  
Atomic Force ◽  
Safe Limits ◽  
Ft Ir ◽  
Recreational Use

With increasing global water temperatures and nutrient runoff in recent decades, the blooming season of algae lasts longer, resulting in toxin concentrations that exceed safe limits for human consumption and for recreational use. From the different toxins, microcystin-LR has been reported as the main cyanotoxin related to liver cancer, and consequently its abundance in water is constantly monitored. In this work, we report a methodology for decorating cellulose nanofibrils with β-cyclodextrin or with poly(β-cyclodextrin) which were tested for the recovery of microcystin from synthetic water. The adsorption was followed by Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), allowing for real-time monitoring of the adsorption behavior. A maximum recovery of 196 mg/g was obtained with the modified by cyclodextrin. Characterization of the modified substrate was confirmed with Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), and Atomic Force Microscopy (AFM).

Investigation of a stimuli-responsive copolymer by atomic force microscopy

Polymer ◽  
2000 ◽  
Vol 41 (18) ◽  
pp. 6723-6727 ◽  
Author(s):  
H.M Zareie ◽  
E Volga Bulmus ◽  
A.P Gunning ◽  
A.S Hoffman ◽  
E Piskin ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Stimuli Responsive ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Injectable Thixotropic β–Cyclodextrin–Functionalized Hydrogels Based on Guanosine Quartet Assembly

2021 ◽  
Vol 22 (17) ◽  
pp. 9179
Author(s):  
Monica-Cornelia Sardaru ◽  
Irina Rosca ◽  
Simona Morariu ◽  
Elena-Laura Ursu ◽  
Razvan Ghiarasim ◽  
...  
Keyword(s):  
Potassium Hydroxide ◽  
Antimicrobial Properties ◽  
Potassium Ions ◽  
Self Healing ◽  
X Ray Diffraction ◽  
Active Components ◽  
X Ray ◽  
Force Microscopy ◽  
Rheological Measurements ◽  
Atomic Force

Facile method for the preparation of β–cyclodextrin–functionalized hydrogels based on guanosine quartet assembly was described. A series of seven hydrogels were prepared by linking β–cyclodextrin molecules with guanosine moieties in different ratios through benzene–1,4–diboronic acid linker in the presence of potassium hydroxide. The potassium ions acted as a reticulation agent by forming guanosine quartets, leading to the formation of self–sustained transparent hydrogels. The ratios of the β–cyclodextrin and guanosine components have a significant effect on the internal structuration of the components and, correspondingly, on the mechanical properties of the final gels, offering a tunablity of the system by varying the components ratio. The insights into the hydrogels’ structuration were achieved by circular dichroism, scanning electron microscopy, atomic force microscopy, and X–ray diffraction. Rheological measurements revealed self–healing and thixotropic properties of all the investigated samples, which, in combination with available cyclodextrin cavities for active components loading, make them remarkable candidates for specific applications in biomedical and pharmaceutical fields. Moreover, all the prepared samples displayed selective antimicrobial properties against S. aureus in planktonic and biofilm phase, the activity also depending on the guanosine and cyclodextrin ratio within the hydrogel structure.

Self-Healing Polymer Films Based on Thiol–Disulfide Exchange Reactions and Self-Healing Kinetics Measured Using Atomic Force Microscopy

2011 ◽  
Vol 45 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Jeong Ae Yoon ◽  
Jun Kamada ◽  
Kaloian Koynov ◽  
Jake Mohin ◽  
Renaud Nicolaÿ ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Polymer Films ◽  
Self Healing ◽  
Exchange Reactions ◽  
Force Microscopy ◽  
Disulfide Exchange ◽  
Atomic Force

Preparation and Self-Assembling of PLA-b-PNIPAM-b-PS Triblock Copolymer Thin Films

2021 ◽  
Vol 21 (4) ◽  
pp. 2174-2184
Author(s):  
Diansen Zhang ◽  
Yuzheng Xia ◽  
Hongliang Gong ◽  
Dong Zhang ◽  
Xiaonong Chen ◽  
...  
Keyword(s):  
Microphase Separation ◽  
Film Surface ◽  
Chemical Compositions ◽  
Stimuli Responsive ◽  
Porous Films ◽  
Force Microscopy ◽  
Self Assembling ◽  
Atomic Force ◽  
Reversible Addition ◽  
Self Assembled

Polylactide-b-poly(N-isopropylacrylamide)-b-polystyrene (PLA-b-PNIPAM-b-PS) triblock copolymers (tri-BCPs) with various chemical compositions (block ratio) were prepared from the combination of ring-opening polymerization and reversible addition-fragmentation chain transfer polymerization. Subsequently, the self-assembling behaviors of these tri-BCP films obtained from spin-coating were investigated by annealing them under different solvent atmosphere. We found that these films could self-assemble into various morphologies due to the microphase separation of incompatible copolymer blocks. Atomic force microscopy confirmed the perpendicular cylindrical morphology self-assembled from PLA4.5k-b-PNIPAM5.2k-b-PS22.4k tri-BCP film under mixed solvent atmosphere of toluene/acetone (7:3, v/v). Self-assembled PLA cylinders are evenly distributed among the PS matrix and perpendicular to the film surface, with PNIPAM component taking place at the PLA/PS interphase. Furthermore, by etching the degradable PLA component, porous PS film decorated with PNIPAM “brushes” hoisting channels were generated. This work provides a facile method and detailed protocol for fabricating stimuli-responsive porous films which are promising for thermoresponsive “smart” separation technologies.

Multi-stimuli responsive self-healing metallo-hydrogels: tuning of the gel recovery property

2014 ◽  
Vol 50 (18) ◽  
pp. 2356-2359 ◽  
Author(s):  
Shibaji Basak ◽  
Jayanta Nanda ◽  
Arindam Banerjee
Keyword(s):  
Chain Length ◽  
The Self ◽  
Self Healing ◽  
Stimuli Responsive ◽  
Healing Property

Self-healable, multi-stimuli responsive metallo-hydrogels based on a series of tyrosine containing amphiphiles have been discovered. Formation of these metallo-gels is highly selective to Ni2+ ions. Moreover, the self-healing property can be modulated by varying the chain length of the corresponding gelator amphiphiles.

scholarly journals Advanced Methods for the Characterization of Supramolecular Hydrogels

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 158
Author(s):  
Bridget R. Denzer ◽  
Rachel J. Kulchar ◽  
Richard B. Huang ◽  
Jennifer Patterson
Keyword(s):  
Surface Characterization ◽  
State Of The Art ◽  
Self Healing ◽  
Rheological Characterization ◽  
Future Directions ◽  
Characterization Methods ◽  
Force Microscopy ◽  
Atomic Force ◽  
Promising Type

With the increased research on supramolecular hydrogels, many spectroscopic, diffraction, microscopic, and rheological techniques have been employed to better understand and characterize the material properties of these hydrogels. Specifically, spectroscopic methods are used to characterize the structure of supramolecular hydrogels on the atomic and molecular scales. Diffraction techniques rely on measurements of crystallinity and help in analyzing the structure of supramolecular hydrogels, whereas microscopy allows researchers to inspect these hydrogels at high resolution and acquire a deeper understanding of the morphology and structure of the materials. Furthermore, mechanical characterization is also important for the application of supramolecular hydrogels in different fields. This can be achieved through atomic force microscopy measurements where a probe interacts with the surface of the material. Additionally, rheological characterization can investigate the stiffness as well as the shear-thinning and self-healing properties of the hydrogels. Further, mechanical and surface characterization can be performed by micro-rheology, dynamic light scattering, and tribology methods, among others. In this review, we highlight state-of-the-art techniques for these different characterization methods, focusing on examples where they have been applied to supramolecular hydrogels, and we also provide future directions for research on the various strategies used to analyze this promising type of material.

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