Rheological properties of polymer chains at a copper oxide surface: Impact of the chain length, surface coverage, and grafted polymer shape

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
José G. Solano Canchaya ◽  
Germain Clavier ◽  
Sébastien Garruchet ◽  
Benoit Latour ◽  
Nicolas Martzel ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Rheological Properties ◽  
Chain Length ◽  
Surface Coverage ◽  
Polymer Chains ◽  
Oxide Surface ◽  
Grafted Polymer ◽  
Polymer Shape

scholarly journals Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1636
Author(s):  
Stella Afroditi Mountaki ◽  
Maria Kaliva ◽  
Konstantinos Loukelis ◽  
Maria Chatzinikolaidou ◽  
Maria Vamvakaki
Keyword(s):  
Carboxylic Acid ◽  
Chain Length ◽  
Main Chain ◽  
Alkyl Chain ◽  
Click Reaction ◽  
Irradiation Time ◽  
Alkyl Chain Length ◽  
Polymer Chains ◽  
Condensation Polymerization ◽  
L929 Fibroblast

Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.

Graft Polymers Derived from Natural Rubber

1956 ◽  
Vol 29 (1) ◽  
pp. 99-105 ◽  
Author(s):  
G. F. Bloomfield ◽  
F. M. Merrett ◽  
F. J. Popham ◽  
P. Mc L. Swift
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Transfer Reaction ◽  
Polymer Chains ◽  
Vinyl Monomers ◽  
Grafted Polymer ◽  
Polymeric Chains ◽  
Graft Polymers ◽  
Direct Growth

Abstract Graft polymers result when vinyl monomers are polymerized in the presence of natural rubber, either in solution or as latex, and some of the polymeric chains become attached to the rubber molecules. The properties of the natural rubber can be widely modified according to the nature and the amount of the grafted polymer. The polymer-modified natural rubber appears to be produced by direct growth of polymer chains on to rubber molecules rather than by a transfer reaction involving the rubber. Graft polymers of styrene and methyl methacrylate with natural rubber can be compounded and cured to give light-colored articles of good tensile strength, and rubber-methyl methacrylate graft polymers have outstanding flex-cracking and fatigue resistance.

X-ray photoelectron spectroscopy study of the interaction of methanol with polycrystalline copper oxide surface

1996 ◽  
Vol 11 (7) ◽  
pp. 1605-1608 ◽  
Author(s):  
S. Badrinarayanan ◽  
A. B. Mandale ◽  
S. R. Sainkar
Keyword(s):  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Low Dose ◽  
Dissociative Adsorption ◽  
Methanol Decomposition ◽  
Oxide Surface ◽  
Polycrystalline Copper ◽  
Spectroscopy Study ◽  
Methanol Vapor ◽  
X Ray

Methanol decomposition on a clean polycrystalline copper oxide surface was studied by x-ray photoelectron spectroscopy (XPS). Methanol was adsorbed at 133 K and desorbed over a broad temperature range. When CuO was exposed to a very low dose of methanol vapor, dissociative adsorption takes place, leading to the formation of CH3O and H2O. This is attributed to the presence of preadsorbed oxygen on the CuO surface.

scholarly journals Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4130
Author(s):  
Svetlana A. Glukhova ◽  
Vyacheslav S. Molchanov ◽  
Boris V. Lokshin ◽  
Andrei V. Rogachev ◽  
Alexey A. Tsarenko ◽  
...  
Keyword(s):  
3D Printing ◽  
Rheological Properties ◽  
Shear Thinning ◽  
Halloysite Nanotubes ◽  
Polymer Chains ◽  
Cross Linking ◽  
Saxs Data ◽  
Nanocomposite Hydrogels ◽  
Embedded Network ◽  
The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

scholarly journals Effect of Structure of Polymers Grafted from Graphene Oxide on the Compatibility of Particles with a Silicone-Based Environment and the Stimuli-Responsive Capabilities of Their Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 591 ◽  
Author(s):  
Monika Zygo ◽  
Miroslav Mrlik ◽  
Marketa Ilcikova ◽  
Martina Hrabalikova ◽  
Josef Osicka ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Graphene Oxide ◽  
Radical Polymerization ◽  
Polymer Brushes ◽  
Silicone Oil ◽  
Polymer Chains ◽  
Butyl Methacrylate ◽  
Raman Shift ◽  
Stimuli Responsive ◽  
Grafted Polymer

This study reports the utilization of controlled radical polymerization as a tool for controlling the stimuli-responsive capabilities of graphene oxide (GO) based hybrid systems. Various polymer brushes with controlled molecular weight and narrow molecular weight distribution were grafted from the GO surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The modification of GO with poly(n-butyl methacrylate) (PBMA), poly(glycidyl methacrylate) (PGMA), poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) and poly(methyl methacrylate) (PMMA) was confirmed by thermogravimetric analysis (TGA) coupled with online Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Various grafting densities of GO-based materials were investigated, and conductivity was elucidated using a four-point probe method. Raman shift and XPS were used to confirm the reduction of surface properties of the GO particles during SI-ATRP. The contact angle measurements indicated the changes in the compatibility of GOs with silicone oil, depending on the structure of the grafted polymer chains. The compatibility of the GOs with poly(dimethylsiloxane) was also investigated using steady shear rheology. The tunability of the electrorheological, as well as the photo-actuation capability, was investigated. It was shown that in addition to the modification of conductivity, the dipole moment of the pendant groups of the grafted polymer chains also plays an important role in the electrorheological (ER) performance. The compatibility of the particles with the polymer matrix, and thus proper particles dispersibility, is the most important factor for the photo-actuation efficiency. The plasticizing effect of the GO-polymer hybrid filler also has a crucial impact on the matrix stiffness and thus the ability to reversibly respond to the external light stimulation.

scholarly journals Oil Deposition on Polymer Brush-Coated NF Membranes

Membranes ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 168 ◽  
Author(s):  
Anh Vu ◽  
Naama Segev Mark ◽  
Guy Z. Ramon ◽  
Xianghong Qian ◽  
Arijit Sengupta ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Polymer Brush ◽  
Operating Mode ◽  
Feed Solution ◽  
Polymer Chains ◽  
Membrane Properties ◽  
Solution Temperature ◽  
Oil Droplets ◽  
Grafted Polymer

Membrane-based processes are attractive for treating oily wastewaters. However, membrane fouling due to the deposition of oil droplets on the membrane surface compromises performance. Here, real-time observation of the deposition of oil droplets by direct confocal microscopy was conducted. Experiments were conducted in dead-end and crossflow modes. Base NF 270 nanofiltration membranes as well as membranes modified by grafting poly(N-isopropylacrylamide) chains from the membrane surface using atom transfer radical polymerization were investigated. By using feed streams containing low and high NaCl concentrations, the grafted polymer chains could be induced to switch conformation from a hydrated to a dehydrated state, as the lower critical solution temperature for the grafted polymer chains moved above and below the room temperature, respectively. For the modified membrane, it was shown that switching conformation of the grafted polymer chains led to the partial release of adsorbed oil. The results also indicate that, unlike particles such as polystyrene beads, adsorption of oil droplets can lead to coalescence of the adsorbed oil droplets on the membrane surface. The results provide further evidence of the importance of membrane properties, feed solution characteristics, and operating mode and conditions on membrane fouling.

ATR Spectroscopic Study of PMMA/PDMS Graft Copolymers Using a Barrier Layer Method

1995 ◽  
Vol 49 (4) ◽  
pp. 513-519 ◽  
Author(s):  
Eva Marand ◽  
L. Mike Smartt
Keyword(s):  
Thin Films ◽  
Copper Oxide ◽  
Spectroscopic Study ◽  
Penetration Depth ◽  
Barrier Layer ◽  
Graft Copolymers ◽  
Oxide Surface ◽  
Concentration Profiles ◽  
Oxide Interface ◽  
Layer Method

The use of an intermediate barrier layer to vary the penetration depth in an ATR experiment is investigated. Both theoretical and experimental results suggest that this method may be useful in probing concentration profiles away from the interface, particularly in the case of thin films, where variable-angle methods have limitations. Application of this technique in the study of poly(methylmethacrylate)/poly(dimethylsiloxane) (PMMA/PDMS) graft copolymers deposited onto a copper oxide surface indicates a preferential presence of the siloxane component at the oxide interface, a concentration which tends to decrease with increasing distance into the bulk of the sample film.

Sign in / Sign up

Export Citation Format

Share Document