Linear viscoelasticity of thermoassociative chitosan-g-poly(N-isopropylacrylamide) copolymer

Seetapan, Nispa; Mai-ngam, Katanchalee; Plucktaveesak, N.; Sirivat, Anuvat

doi:10.1007/s00397-005-0055-1

Cited by 31 publications

(23 citation statements)

References 31 publications

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“…The results obtained seem to be in agreement with previous work performed by Kim et al., 37 Seetapan et al, 38 and Lee et al 39 Figure 2 presents the FTIR spectra of PNIPAAm homopolymer, chitosan-graft-NIPAAm, and chitosan. A peak can be observed in the spectrum of the grafted product at around 1120 cm À1 that could be assigned to the CÀO stretching vibration of chitosan.…”

Section: Buildup and Characterization Of Pnipaam-based Filmssupporting

confidence: 95%

Dual Responsive Nanostructured Surfaces for Biomedical Applications

2011

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In this paper, we describe the construction and characteristics of thermoresponsive, thin nanostructured films prepared by layer-by-layer sequential assembly of chitosan-graft-NIPAAm and alginate. FTIR and (1)H NMR spectra have confirmed the introduction of NIPAAm moieties onto the chitosan backbone. The LCST of the synthesized copolymer was found to be around 31-33 °C. The formation of the polyelectrolyte multilayers containing the copolymer and alginate was followed in situ by quartz crystal microbalance with dissipation monitoring technique and ex situ by UV-vis measurements. Our results revealed the linear increase of the multilayer film growth and the influence of the presence of salt. Moreover, AFM analysis has confirmed that PNIPAAm is able to reconform upon temperature swaps even when combined with other layers in a polyelectrolyte multilayer, demonstrating that the nanoassemblies are thermoresponsive. Preliminary results showed that, upon reducing culture temperature below PNIPAAm LCST, a gradual detachment of cell sheets from these PNIPAAm-based coatings has occurred.

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Section: Buildup and Characterization Of Pnipaam-based Filmssupporting

confidence: 95%

Dual Responsive Nanostructured Surfaces for Biomedical Applications

2011

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“…Nowadays, grafting PNIPAM side chains on the chitosan backbone constitutes a crescent area of research, since it bonds the most studied thermosensitive polymer with the most outstanding cationic polysaccharide, to reach dual temperature and pH responsive materials with remarkable properties [33,[111][112][113][114] .…”

Section: Combination Of Ph and Thermosensitive Properties Through Gramentioning

confidence: 99%

Development of dual-sensitive smart polymers by grafting chitosan with poly (<italic>N</italic>-isopropylacrylamide): an overview

2015

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A great deal of research on polymers over the past two decades has been focused on the development of stimuli-responsive polymers to obtain materials able to respond to specific surroundings. In this paper, an overview is presented of the concepts, behavior and applicability of these "smart polymers". Polymers that are temperature-or pH-sensitive are discussed in detail, including the response mechanisms and types of macromolecules, because they are easy to handle and have a wide range of applications. Finally, the combination of pH and temperature responsive properties by means of graft copolymerization of chitosan with poly (N-isopropylacrylamide) (PNIPAM) was chosen to represent some synthetic routes and properties of dual-sensitive polymeric systems developed currently.

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“…It is always a great challenge in oil recovery to keep high viscosity of polymer displacement agent at a high temperature because the viscosity of most current oil displacement agents will decrease upon heating or in a high-temperature environment [9,11]. Differing from most of the commonly used polymers, which can hardly solve this problem [7,13], the thermo-thickening polymers whose viscosity can be enhanced during heating process have great potential to be used in enhanced oil recovery as well as water treatment and paper manufacturing [14]. In addition, because the thermo-thickening polymers with high concentration usually present a sol-gel transition temperature, they also have great potential in controlled permeation [7], tissue engineering [13], drug delivery [2,6], and so on.…”

Section: Introductionmentioning

confidence: 99%

“…For CS complexes, thermo-thickening behaviors were less reported thus far except chitosan/poly(vinyl alcohol) (CS/PVA) [27] and chitosan/glycerophosphate (CS/β-GP) [29]. For CS derivatives, modification by poly-N-isopropylacrylamide (PNIPAM) is a common way to realize thermo-thickening [13,31], and recently, the carboxymethyl chitin also shows a novel thermo-thickening, which is pH-and temperature-dependent [33]. As there are many kinds of molecular interactions involved in these aqueous solutions mentioned above, it is difficult to elucidate the molecular mechanism of the thermo-thickening behavior of these complex systems.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and Rheological Behavior of Chitosan-Grafted-Polyacrylamide in Aqueous Solution upon Heating

2020

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In this work, the transformation of chitosan-grafted-polyacrylamide (GPAM) aggregates in aqueous solution upon heating was explored by cryo-electron microscope (cryo-TEM) and dynamic light scattering (DLS), and larger aggregates were formed in GPAM aqueous solution upon heating, which were responsible for the thermo-thickening behavior of GPAM aqueous solution during the heating process. The heating initiates a transformation from H-bonding aggregates to a large-sized cluster formed by self-assembled hydrophobic chitosan backbones. The acetic acid (HAc) concentration has a significant effect on the thermo-thickening behavior of GPAM aqueous solution; there is a critical value of the concentration (>0.005 M) for the thermo-thickening of 10 mg/mL GPAM solution. The concentration of HAc will affect the protonation degree of GPAM, and affect the strength of the electrostatic repulsion between GPAM molecular segments, which will have a significant effect on the state of the aggregates in solution. Other factors that have an influence on the thermo-thickening behavior of GPAM aqueous solution upon heating were investigated and discussed in detail, including the heating rate and shear rate.

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Linear viscoelasticity of thermoassociative chitosan-g-poly(N-isopropylacrylamide) copolymer

Cited by 31 publications

References 31 publications

Dual Responsive Nanostructured Surfaces for Biomedical Applications

Dual Responsive Nanostructured Surfaces for Biomedical Applications

Development of dual-sensitive smart polymers by grafting chitosan with poly (<italic>N</italic>-isopropylacrylamide): an overview

Dynamics and Rheological Behavior of Chitosan-Grafted-Polyacrylamide in Aqueous Solution upon Heating

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