Fast temperature-responsive nanocomposite PNIPAM hydrogels with controlled pore wall thickness: Force and rate of T-response

Depa, Katarzyna; Strachota, Adam; Šlouf, Miroslav; Hromádková, Jiřina

doi:10.1016/j.eurpolymj.2012.09.007

Cited by 43 publications

(36 citation statements)

References 36 publications

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“…Poly(N-isopropylacrylamide) (PNIPA) based hydrogels are among the most studied temperature-responsive systems, as they exhibit a volume phase transition around 34°C, close to the temperature of the (human) body. This property can be of use in biomedical applications [11,12]. These systems nevertheless have drawbacks, such as weak mechanical strength, which restricts applications involving repetitive loading.…”

Section: Introductionmentioning

confidence: 99%

Thermal sensitivity of carbon nanotube and graphene oxide containing responsive hydrogels

Manek

Berke

Miklósi

et al. 2016

Express Polym. Lett.

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Abstract.Comparative investigations are reported on poly(N-isopropylacrylamide) (PNIPA) gels of various carbon nanotube (CNT) and graphene oxide (GO) contents synthesized under identical conditions. The kind and concentration of the incorporated carbon nanoparticles (CNPs) influence the swelling and stress-strain behaviour of the composites. Practically independently of the filler content, incorporation of CNPs appreciably improves the fracture stress properties of the gels. The time constant and the swelling ratio of the shrinkage following an abrupt increase in temperature of the swelling medium from 20 to 50°C can be adjusted by selecting both the type and the amount of nanoparticle loading. This offers a means of accurately controlling the deswelling kinetics of drug release with PNIPA systems, and could be employed in sensor applications where fast and excessive shrinkage are a significant drawback. Both CNTs and GO enhance the infrared sensitivity of the PNIPA gel, thus opening a route for the design of novel drug transport and actuator systems. It is proposed that the influence of the CNPs depends more on their surface reactivity during the gel synthesis rather than on their morphology. One of the important findings of this study is the existence of a thermally conducting network in the GO filled gels.

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Section: Introductionmentioning

confidence: 99%

Thermal sensitivity of carbon nanotube and graphene oxide containing responsive hydrogels

Manek

Berke

Miklósi

et al. 2016

Express Polym. Lett.

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“…Also,  is the interaction parameter of the network which is a function of temperature and the polymer volume fraction for the temperature sensitive PNIPAM hydrogel. In addition, 0 A , 0 B , 1 A and 1 B are material parameters adopted for the experiments reported by Afroze et al [37]. Using swelling constraint, equation (6), the total free energy density is:…”

Section: Model Descriptionmentioning

confidence: 99%

“…Smart hydrogels composed of covalently cross-linked polymeric network which can response to environmental stimuli such as temperature [1][2][3], pH [4][5][6], mechanical load [7,8], ionic and salt concentration [9,10], light [11][12][13] and electric field [14,15] and can imbibe large amount of water and experience a large deformation. These materials can be used as sensor and actuator simultaneously.…”

Section: Introductionmentioning

confidence: 99%

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Study of swelling behavior of temperature sensitive hydrogels considering inextensibility of network

Mazaheri

2018

Scientia Iranica

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In this work, the equilibrium swelling of temperature sensitive hydrogel networks is studied with an emphasis on the chain locking of the network. Using Gent model for elastic part of free energy and modifying the mixing part of the free energy, a continuous model is developed which consider inextensibility of the network chains and has a good agreement with the experimental data particularly for smaller values of crosslinking density of the network and larger values of the swelling ratio. After validating the modified model, it is employed for the studying the inhomogeneous swelling of a spherical shell on a hard core both analytically and numerically.The analytical solution is used for validating the numerical method. Finally, the inhomogeneous swelling of a bilayer beam with an active temperature sensitive hydrogel is investigated and the results are presented. The obtained results show the importance level of considering the chain locking in swelling of the network in the applied problems.

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“…This makes them very attractive for example in drug delivery [9,10], or as sensors [11], actuators [12,13], microvalves [14]. Poly(Nisopropylacrylamide) (PNIPA) is one of the most popular temperature sensitive responsive hydrogel, owing to its peculiar volume phase transition temperature (VPTT) that is at ~34 °C, close to the temperature of the human body [9,15]. Despite the above mentioned advantages hydrogels have several limitations as well (e.g.…”

Section: Introductionmentioning

confidence: 99%

Graphene derivatives in responsive hydrogels: Effect of concentration and surface chemistry

Berke

Sós

Bérczes

et al. 2017

European Polymer Journal

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Reduced graphene oxide (RGO) containing composite hydrogels, based on poly(Nisopropylacrylamide) (PNIPA) were prepared by two different methods: i) by incorporating RGO directly into the polymer matrix; ii) applying a post-synthesis reduction of the grapheneoxide (GO) already incorporated into the polymer. The samples were compared by various microscopic (small angle neutron scattering, differential scanning calorimetry, 1 H NMR spectroscopy, thermogravimetry) and macroscopic (kinetic and equilibrium swelling properties and mechanical testing) techniques. Results from microscopic and macroscopic measurements show that the dispersity of the nanoparticles as well as their interaction with the polymer chains are influenced by their surface chemistry. Incorporation of nanoparticles limits the shrinkage and slows down the kinetics of the thermal response. Both thermogravimetric and solid-state 1 H NMR measurements confirmed strong polymernanoparticle interaction when hydrophilic GO was used in the synthesis. In these cases, the slow thermal response may be explained by the decrease of the free volume inside the nanocomposite matrix caused by a hypernodal structure. Our results imply that both the chemistry and the concentration of incorporated graphene derivatives are promising in tuning the thermal responsivity of PNIPA.

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Fast temperature-responsive nanocomposite PNIPAM hydrogels with controlled pore wall thickness: Force and rate of T-response

Cited by 43 publications

References 36 publications

Thermal sensitivity of carbon nanotube and graphene oxide containing responsive hydrogels

Thermal sensitivity of carbon nanotube and graphene oxide containing responsive hydrogels

Study of swelling behavior of temperature sensitive hydrogels considering inextensibility of network

Graphene derivatives in responsive hydrogels: Effect of concentration and surface chemistry

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