Porous hybrid poly(N-isopropylacrylamide) hydrogels with very fast volume response to temperature and pH

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F19%3A00508103" target="_blank" >RIV/61389013:_____/19:00508103 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0014305719313965?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0014305719313965?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.eurpolymj.2019.109213" target="_blank" >10.1016/j.eurpolymj.2019.109213</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Porous hybrid poly(N-isopropylacrylamide) hydrogels with very fast volume response to temperature and pH

Popis výsledku v původním jazyce

Super-porous hydrogels were prepared, which are able of fast to ultra-fast volume response to temperature and to pH, and thus show a promise as soft actuators. The hydrogels are based on the poly(N-isopropylacrylamide) (PNIPAm)/silica nanocomposite, in which the filler strongly raises the modulus and also stabilizes the pore walls against collapse during deswelling. The well-interconnected sub-millimetre-sized porosity was generated via solvent freezing during synthesis. The gels morphology makes possible both ultra-fast deswelling and re-swelling (5.5 s for 70% in both directions, in response to T). This work focused on introducing pH-responsiveness into the gels. To this end, 1–10 mol% of sodium methacrylate (SMA) were incorporated as co-monomer. Distinct pH-responsiveness was achieved already at 1 mol% of SMA. Increase of SMA content markedly expands the temperature range of the pH-responsiveness and raises its amplitude. At the same time the increase of SMA content reduces the amplitude of the T-responsiveness, which is only moderate at 10 mol% SMA. The rate of pH-response was found to be always slower than in case of the T-response: 75 s are needed for 70% of de-swelling, and 90 min for 70% of re-swelling. The vast difference in the rates of pH- and T- response can be explained by different mechanisms of stimulus propagation (momentum transfer for T, vs. diffusion for pH) and by the mechanical effect of a contracting stiff and porous surface layer (much faster pH-deswelling than re-swelling). More generally, in case of the pH-stimulus, the mechanistic limits of its propagation in ‘simple’ porous gels become evident.

Název v anglickém jazyce

Porous hybrid poly(N-isopropylacrylamide) hydrogels with very fast volume response to temperature and pH

Popis výsledku anglicky

Super-porous hydrogels were prepared, which are able of fast to ultra-fast volume response to temperature and to pH, and thus show a promise as soft actuators. The hydrogels are based on the poly(N-isopropylacrylamide) (PNIPAm)/silica nanocomposite, in which the filler strongly raises the modulus and also stabilizes the pore walls against collapse during deswelling. The well-interconnected sub-millimetre-sized porosity was generated via solvent freezing during synthesis. The gels morphology makes possible both ultra-fast deswelling and re-swelling (5.5 s for 70% in both directions, in response to T). This work focused on introducing pH-responsiveness into the gels. To this end, 1–10 mol% of sodium methacrylate (SMA) were incorporated as co-monomer. Distinct pH-responsiveness was achieved already at 1 mol% of SMA. Increase of SMA content markedly expands the temperature range of the pH-responsiveness and raises its amplitude. At the same time the increase of SMA content reduces the amplitude of the T-responsiveness, which is only moderate at 10 mol% SMA. The rate of pH-response was found to be always slower than in case of the T-response: 75 s are needed for 70% of de-swelling, and 90 min for 70% of re-swelling. The vast difference in the rates of pH- and T- response can be explained by different mechanisms of stimulus propagation (momentum transfer for T, vs. diffusion for pH) and by the mechanical effect of a contracting stiff and porous surface layer (much faster pH-deswelling than re-swelling). More generally, in case of the pH-stimulus, the mechanistic limits of its propagation in ‘simple’ porous gels become evident.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

<a href="/cs/project/GA19-04925S" target="_blank" >GA19-04925S: Pokročilé inteligentní samoregenerující se nanokompozítní hydrogely citlivé na vnější podněty</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Polymer Journal

ISSN

0014-3057

e-ISSN

—

Svazek periodika

120

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

14

Strana od-do

1-14

Kód UT WoS článku

000498309000005

EID výsledku v databázi Scopus

2-s2.0-85071879458