SANS and DLS Study of Tacticity Effects on Hydrophobicity and Phase Separation of Poly(<i>N</i>-isopropylacrylamide)

Nishi, Kengo; Hiroi, Takashi; Hashimoto, Kei; Fujii, Kenta; Han, Young‐Soo; Kim, Tae‐Hwan; Katsumoto, Yukiteru; Shibayama, Mitsuhiro

doi:10.1021/ma401349v

Cited by 69 publications

(88 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, the transmittance curves of the m = 60 %a nd m = 64 %, w = 0.01 solutions were broader in comparison to their m = 46 %c ounterpart. This last observation motivated Nishi et al [35] to study the phase separation of PNIPAM solutions with m = 46, 48, 51, 55, 56, and 58 %u sing dynamic light scattering and small angle neutron scattering (SANS). Their results suggest that the coils shrink significantly prior to aggregation for the lower m samples while in the isotactic rich case chain shrinking and aggregation occur simultaneously.…”

Section: Tacticitymentioning

confidence: 97%

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

2015

View full text Add to dashboard Cite

In 1968, Heskins and Guillet published the first systematic study of the phase diagram of poly(N-isopropylacrylamide) (PNIPAM), at the time a "young polymer" first synthesized in 1956. Since then, PNIPAM became the leading member of the growing families of thermoresponsive polymers and of stimuli-responsive, "smart" polymers in general. Its thermal response is unanimously attributed to its phase behavior. Yet, in spite of 50 years of research, a coherent quantitative picture remains elusive. In this Review we survey the reported phase diagrams, discuss the differences and comment on theoretical ideas regarding their possible origins. We aim to alert the PNIPAM community to open questions in this reputably mature domain.

show abstract

Section: Tacticitymentioning

confidence: 97%

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

2015

View full text Add to dashboard Cite

show abstract

“…This assumption is in accordance with the fact that PNIPAM meso-dyads are more hydrophobic than the racemodyads. 16 It has been shown that the phase separation behavior strongly depends on the PNIPAM tacticity. 17 From transmittance measurements, it was revealed that the LCST tends to decrease with increasing meso-diad content of PNIPAM.…”

Section: Preparation Of Polymeric Nanocapsulesmentioning

confidence: 99%

Polymeric Nanoparticle Engineering: From Temperature-Responsive Polymer Mesoglobules to Gene Delivery Systems

et al. 2014

View full text Add to dashboard Cite

A novel approach for the preparation of nano- and microcapsules in aqueous solutions by using thermoresponsive polymer (TRP) templates (mesoglobules) is described. The method comprised three steps: formation of mesoglobules, coating the templates by seeded radical copolymerization, followed by core dissolution and core removal upon cooling. When mesoglobule entraps biomacromolecules during the process of their formation, it makes it possible to load a controlled amount of bioactive compounds without covalent attachment. Special attention is paid to the mesoglobule dissolution upon cooling, as well as their loading efficiency. Details on the outer shell formation and the possibilities for targeting ligands incorporation and control of the shell porosity are discussed. Finally, the seeded radical copolymerization was used for covering DNA complexes with cationic copolymers bearing TRP blocks. This Review is an attempt to convince researchers of the promising perspectives for using mesoglobules as potential reservoirs, carriers, and transferring agents for biologically active substances.

show abstract

“…All kinds of opposing conclusions, i.e., decrease, increase, and independence of LCST of PNIPAAm on the structural and experimental parameters can be found in the literature (see Table S1 in the Supporting Information and, e.g., refs …”

Section: Introductionmentioning

confidence: 96%

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

Osváth

Iván

2016

Macromol. Chem. Phys.

View full text Add to dashboard Cite

Inappropriately, the critical solution temperature (CST) of lower CST(LCST)‐ or upper CST(UCST)‐type thermoresponsive polymers, measured by one, individual set of conditions, is considered almost exclusively as the LCST or UCST, respectively. These are correctly the minimum or maximum, respectively, of the full phase diagrams. Because the dynamic phase transition depends on the conditions, and no standardized or widely accepted process exists for CST determination, systematic investigations are carried out with the most widely investigated poly(N‐isopropylacrylamide) (PNIPAAm) to unveil the effect of data evaluation, measurement conditions on the transmittance–temperature curves, cloud point (TCP), clearing point (TCL), and heating–cooling hysteresis. The unusual dependence of the fundamental hysteresis parameters, i.e., width of hysteresis (XH) and extent of transmittance recovery (YH), on a broad range of conditions is revealed for the first time. On the basis of the findings, the inflection point of transmittance(absorbance)–temperature curves as TCP and TCL, 0.1 wt% solution, 0.2 °C min−1 heating/cooling steps with 5 min equilibration between the gradual change of temperature, 488 nm wavelength to obtain data comparable to light scattering at this wavelength, and determination of XH and YH are proposed as standard set of conditions.

show abstract

SANS and DLS Study of Tacticity Effects on Hydrophobicity and Phase Separation of Poly(N-isopropylacrylamide)

Cited by 69 publications

References 37 publications

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

Polymeric Nanoparticle Engineering: From Temperature-Responsive Polymer Mesoglobules to Gene Delivery Systems

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

Contact Info

Product

Resources

About