Origin of the low-frequency plateau and the light-scattering slow mode in semidilute poly(ethylene glycol) solutions

Soft Matter ◽  
2019 ◽  
Vol 15 (12) ◽  
pp. 2666-2676 ◽  
Author(s):  
Martha Koziol ◽  
Karl Fischer ◽  
Sebastian Seiffert

The low-frequency plateau often found in the rheological spectra of semidilute polymer solutions is shown to be an artifact due to imprecise phase-angle determination; furthermore, the slow mode in the dynamic light scattering autocorrelation function of such solutions is shown to result from minor fractions of 20–200 nm sized impurities.

Soft Matter ◽  
2018 ◽  
Vol 14 (24) ◽  
pp. 5039-5047
Author(s):  
Ksenija Kogej ◽  
Jaka Štirn ◽  
Jurij Reščič

After addition of poly(ethylene glycol) to a solution of poly(sodium methacrylate), the slow-mode dynamic light scattering signal reappears.


Polimery ◽  
2021 ◽  
Vol 66 (9) ◽  
pp. 451-458
Author(s):  
Nur Fathin Amirah Shafie ◽  
Mohd Yusof Hamzah ◽  
Roshafima Rasit Ali

The influence of 2-(dimethylamino)ethyl methacrylate (DMAEMA) concentration on the temperature sensitivity of nanogels based on N-isopropylacrylamide (NIPAAM), poly(vinylpyrrolidone) (PVP), poly(ethylene glycol) diacrylate (PEGDA) by gamma radiation induced polymerization was investigated. Dynamic light scattering (DLS) and zeta potential measurements were used to characterize the nanogels. Temperature has been found to cause the nanogel particles to swell and shirnkage, allowing controlled dosing of the drug contained in capsules. The developed nanogels are promising materials with great potential for biomedical applications.


1987 ◽  
Vol 244 (1) ◽  
pp. 87-92 ◽  
Author(s):  
A P Dawson ◽  
G Hills ◽  
J G Comerford

1. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]), if added before GTP, blocks both Ca2+ efflux promoted by GTP and the effect of GTP on enhancement of inositol 1,4,5-triphosphate (IP3)-promoted Ca2+ release from preloaded microsomal vesicles. If, however, GTP[S] is added after GTP, it does not reverse the Ca2+ efflux promoted by GTP, nor does it inhibit IP3-promoted Ca2+ release. 2. The effect of GTP in enhancing IP3-promoted Ca2+ release is maintained after washing the microsomal vesicles free of added GTP. After this treatment, enhancement of IP3-promoted Ca2+ efflux can be observed in the absence of poly(ethylene glycol). 3. Electron microscopy shows that during GTP treatment of microsomal vesicles there is rapid production of very large vesicular structures, apparently produced by fusion of smaller vesicles. 4. Light-scattering changes are detectable during the fusion process. 5. Both Ca2+ efflux promoted by GTP and the enhancement of IP3-promoted Ca2+ release seen in the presence of GTP can probably be attributed to GTP-dependent vesicle fusion.


2016 ◽  
Vol 1452 ◽  
pp. 107-115 ◽  
Author(s):  
Ziliang Zhao ◽  
Qi Li ◽  
Xiangling Ji ◽  
Rumiana Dimova ◽  
Reinhard Lipowsky ◽  
...  

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