Thermally Responsive Amphiphilic Conetworks and Gels Based on Poly(<i>N</i>-isopropylacrylamide) and Polyisobutylene

Kali, Gergely; Vavra, Szilvia; László, Krisztina; Iván, Béla

doi:10.1021/ma400535r

Cited by 80 publications

(71 citation statements)

References 89 publications

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“…In general, the VPTT of the PNIPA-based gels can be tuned by changing its hydrophilic/ hydrophobic balance, e.g., by copolimerization [46,47]. Our DSC measurements show no difference in the VPTT and the corresponding specific enthalpy (33.90.1 °C and 522 J/g, respectively) in the systems in Figure 5a.…”

Section: Resultsmentioning

confidence: 71%

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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Section: Resultsmentioning

confidence: 71%

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

Berke

Sós

Bérczes

et al. 2017

European Polymer Journal

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“…P(S-NIPAM-MAA-PEGMA) hydrogel particles exhibit different morphology with central darker parts possibly represents the hydrophobic PS rich segment. The hydrophobic-hydrophobic interactions among PS segments in amphiphilic P(S-NIPAM-MAA-PEGMA) conetwork led to the reorientation of polymer chains forming core-shell type microgels in water [60][61][62][63][64]. Compared to P(S-NIPAM-MAA-PEGMA) hydrogel particles the size of Fe 3 O 4 / SiO 2 /P(S-NIPAM-MAA-PEGMA) composite hydrogel particles decreases after blending with Fe 3 O 4 / SiO 2 nanocomposite particles.…”

Section: Absorption Of Biomoleculesmentioning

confidence: 99%

“…MMA/MAA was added to improve the solubility of styrene in the aqueous dispersion media for facilitating smooth copolymerization with NIPAM as the latter in absence of MMA/MAA may produce larger proportion of water soluble homopolymer due to its comparatively high reaction rate. The hydrophobichydrophobic interactions among hydrophobic PS-PMMA or PS segments in the prepared conetworks are expected to form microgels in water, a phenom-enon generally observed for amphiphilic copolymer networks consisting of hydrophilic and hydrophobic polymer segments [60][61][62][63][64] 4 OH and other chemicals were of analytical grade. Ethanol and deionized water was distilled using a glass (Pyrex) distillation apparatus.…”

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confidence: 99%

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

Ahmad¹,

Sultana²,

Alam³

et al. 2016

Express Polym. Lett.

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Abstract. The inclusion of super paramagnetic iron oxide (Fe 3 O 4 ) nanoparticles in stimuli-responsive hydrogel is expected to enhance the application potential for cellular therapy in cell labeling, separation and purification, protein immobilization, contrasting enhancement in magnetic resonance imaging (MRI), localized therapeutic hyperthermia, biosensors etc. in biomedical field. In this investigation two different magnetic and stimuli-responsive composite hydrogel particles with variable surface property were prepared by simply blending Fe 3 O 4 /SiO 2 nanocomposite particles with stimuli-responsive hydrogel particles. Of the hydrogel particles prepared by free-radical precipitation polymerization poly(styrene-N-isopropylacrylamide-methyl methacrylate-polyethylene glycol methacrylate) or P(S-NIPAM-MMA-PEGMA) was temperature-sensitive and poly(S-NIPAM-methacrylic acid-PEGMA) or P(S-NIPAM-MAA-PEGMA) was both temperature-and pH-responsive. The morphological structure, size distributions and volume phase transitions of magnetic and stimuli-responsive composite hydrogel particles were analyzed. Temperature-responsive absorptions of biomolecules were observed on both magnetic and stimuli-responsive Fe 3 O 4 /SiO 2 /P(S-NIPAM-MMA-PEGMA) and Fe 3 O 4 /SiO 2 /P(S-NIPAM-MAA-PEGMA) composite hydrogel particles and separation of particles from the dispersion media could be achieved by applying magnetic field without time consuming centrifugation or decantation method.

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“…Hydrogels may be synthesized via several different ways such as thermal- [25], redox- [26], RAFT- [27,28] and photopolymerization [29]. This last method that corresponds to a photoinitiated radical polymerization of multifunctional monomers that produce highly crosslinked polymers, has several advantages over conventional ones like spatial and temporal control, fast curing and reaction rates at room temperature, solvent-free formulation, among others.…”

Section: Introductionmentioning

confidence: 99%

In situ silver nanoparticle formation embedded into a photopolymerized hydrogel with biocide properties

et al. 2014

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In situ nanoparticle formation embedded into hydrogel matrix, acting as container and stabilizer for nanoparticle reaction was the focus in this research; this method was realized using AgNO 3 (0.75 and 1.0 M) as silver source for nanoparticle formation; also, monomers (HEMA), cross-linker agents (DEGDMA) and a photoinitiator (Irgacure 651) were used for the hydrogel synthesis. For the reduction of Ag ? ? Ag 0 , the reaction mixture was irradiated with an UV lamp at 365 nm for 30 min; parallel to this process, the hydrogel photopolymerization occurs. All these systems were studied by Infrared and Raman Spectroscopy, optical studies: UV/Vis absorption, thermal studies: differential scanning calorimetry and thermogravimetric analysis, X-ray diffraction, fluorescence X-ray spectroscopy and transmission electronic microscopy. Characterization techniques are capable to detect the presence of non-agglomerated silver nanoparticles homogeneously distributed in all the systems. X-Ray photoemission spectroscopy establishes the presence of Ag 0 and Ag ? as mixture in the synthesized composite. Quantitative assays show that the sample Ag_Hg3-89.5 % (1.0 M) presents an important biocide property, by reducing 99.9 % of bacterium Escherichia coli ATCC 25922 as compared with the alone hydrogel used as control.

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Thermally Responsive Amphiphilic Conetworks and Gels Based on Poly(N-isopropylacrylamide) and Polyisobutylene

Cited by 80 publications

References 89 publications

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

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

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

In situ silver nanoparticle formation embedded into a photopolymerized hydrogel with biocide properties

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