Solution behaviors and microstructures of PNIPAm-P123-PNIPAm pentablock terpolymers in dilute and concentrated aqueous solutions.

The solution behaviors and microstructures of poly(N-isopropylacrylamide)x-poly(ethylene oxide)20-poly(propylene oxide)70-poly(ethylene oxide)20-poly(N-isopropylacrylamide)x (PNIPAmx-PEO20-PPO70-PEO20-PNIPAmx or PNIPAmx-P123-PNIPAmx) pentablock terpolymers with various PNIPAm block lengths in dilute and concentrated aqueous solutions were investigated by micro-differential scanning calorimetry (micro-DSC), static and dynamic light scattering (SLS & DLS), and synchrotron small angle X-ray scattering (SAXS). Two lower critical solution temperatures (LCSTs) were observed for PNIPAmx-P123-PNIPAmx pentablock terpolymers in dilute solutions, which corresponded to LCSTs of PPO and PNIPAm blocks, respectively. The LCST of PPO block shifted from 24.

Interfacial entrapment of noble metal nanoparticles and nanorods capped with amphiphilic multiblock copolymer at a selective liquid-liquid interface.

An amphiphilic multiblock copolymer, [poly(4-vinylpyridine)-b-polystyrene-b-poly(4-vinylpyridine)](n) (P4VP-PS-P4VP)(n) bearing trithiocarbonate moieties (-S-CS-S-), was used as capping agent to fabricate the functional copolymer-capped Au nanoparticles. Due to the amphiphilic character of the multiblock copolymer, the (P4VP-PS-P4VP)(n)-capped Au nanoparticles were able to be entrapped and hence form a stable monolayer thin film at the (DMF-H(2)O)/diethyl ether interface. Note that DMF-H(2)O is a good mixed solvent for P4VP and a nonsolvent for PS, whereas diethyl ether is a good solvent for PS and a nonsolvent for P4VP.

One-pot preparation of hollow silica spheres by using thermosensitive poly(N-isopropylacrylamide) as a reversible template.

Hollow silica nanospheres with mesoporous shells were successfully fabricated with a new one-pot strategy by using a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAm), as a reversible template without the need of further calcination or chemical etching. By simply regulating the solution temperature with respect to the lower critical solution temperature (LCST) of PNIPAm, PNIPAm chains can reversibly form aggregates or dissolve in aqueous solution. The thermosensitive character makes PNIPAm chains behave as soft templates for the formation of core-shell silica nanospheres at elevated temperature (>LCST), and they will then diffuse out of the cores at lower temperature ( View Article and Find Full Text PDF