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Internal nanoparticle structure of temperature-responsive self-assembled PNIPAM-b-PEG-b-PNIPAM triblock copolymers in aqueous solutions: NMR, SANS, and light scattering studies
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SYSNO ASEP 0460134 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Internal nanoparticle structure of temperature-responsive self-assembled PNIPAM-b-PEG-b-PNIPAM triblock copolymers in aqueous solutions: NMR, SANS, and light scattering studies Tvůrce(i) Filippov, Sergey K. (UMCH-V) RID, ORCID, SAI
Bogomolova, Anna (UMCH-V) RID
Kaberov, Leonid I. (UMCH-V) ORCID
Velychkivska, Nadiia (UMCH-V) RID, ORCID
Starovoytova, Larisa (UMCH-V) RID
Černochová, Zulfiya (UMCH-V) RID, ORCID
Rogers, S. E. (GB)
Lau, W. M. (GB)
Khutoryanskiy, V. V. (GB)
Cook, M. T. (GB)Zdroj.dok. Langmuir. - : American Chemical Society - ISSN 0743-7463
Roč. 32, č. 21 (2016), s. 5314-5323Poč.str. 10 s. Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova nanoparticles ; copolymers ; NMP Vědní obor RIV CF - Fyzikální chemie a teoretická chemie CEP GC15-10527J GA ČR - Grantová agentura ČR Institucionální podpora UMCH-V - RVO:61389013 UT WOS 000377151300012 EID SCOPUS 84973345069 DOI 10.1021/acs.langmuir.6b00284 Anotace In this study, we report detailed information on the internal structure of PNIPAM-b-PEG-b-PNIPAM nanoparticles formed from self-assembly in aqueous solutions upon increase in temperature. NMR spectroscopy, light scattering, and small-angle neutron scattering (SANS) were used to monitor different stages of nanoparticle formation as a function of temperature, providing insight into the fundamental processes involved. The presence of PEG in a copolymer structure significantly affects the formation of nanoparticles, making their transition to occur over a broader temperature range. The crucial parameter that controls the transition is the ratio of PEG/PNIPAM. For pure PNIPAM, the transition is sharp; the higher the PEG/PNIPAM ratio results in a broader transition. This behavior is explained by different mechanisms of PNIPAM block incorporation during nanoparticle formation at different PEG/PNIPAM ratios. Contrast variation experiments using SANS show that the structure of nanoparticles above cloud point temperatures for PNIPAM-b-PEG-b-PNIPAM copolymers is drastically different from the structure of PNIPAM mesoglobules. In contrast with pure PNIPAM mesoglobules, where solidlike particles and chain network with a mesh size of 1–3 nm are present, nanoparticles formed from PNIPAM-b-PEG-b-PNIPAM copolymers have nonuniform structure with “frozen” areas interconnected by single chains in Gaussian conformation. SANS data with deuterated “invisible” PEG blocks imply that PEG is uniformly distributed inside of a nanoparticle. It is kinetically flexible PEG blocks which affect the nanoparticle formation by prevention of PNIPAM microphase separation. Pracoviště Ústav makromolekulární chemie Kontakt Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Rok sběru 2017
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