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1. Organic X-Ray Radioluminescent Crystalline Colloidal Arrays Encapsulated in Poly(Ethylene Glycol) Methacrylate Based Hydrogel Films

   https://doi.org/10.1364/BODA.2021.JW1A.12  

   Mell, Sarah ; Jones, Haley W. ; Bandera, Yuriy ; Foulger, Stephen H. ( January 2021 , Biophotonics Congress 2021)

   Due to Coulombic forces, X-ray active copolymer nanoparticles self-assembled into crystalline colloidal arrays which were stabilized through encapsulation in hydrogels. The system was able to emit blue light when pumped with an X-ray source. 

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2. In situ saxs characterization of thermoresponsive behavior of a poly(ethylene glycol)-graft-(poly(vinyl caprolactam)-co-poly(vinyl acetate)) amphiphilic graft copolymer

   https://doi.org/10.1088/1361-6528/acab6d  

   Kennedy, Mitchell A ; Zhang, Yugang ; Bhatia, Surita R ( January 2023 , Nanotechnology)

   Abstract We report the thermoresponsive assembly and rheology of an amphiphilic thermosensitive graft copolymer, poly(ethylene glycol)-graft-(poly(vinyl caprolactam)- co -poly(vinyl acetate)) (commercial name Soluplus ® ), which has been investigated for potential biomedical applications. It has received attention due to is ability to solubilize hydrophobic drugs and for its thickening behavior close to body temperature. Through use of the synchrotron at Brookhaven National Lab, and collaboration with the department of energy, the nanoscale structure and properties can be probed in greater detail. Soluplus ® undergoes two structural changes as temperature is increased; the first, a concentration independent change where samples become turbid at 32 °C. Increasing the temperature further causes the formation of physically associated hydrogels. This sol-gel transition is concentration dependent and occurs at 32 °C for 40 wt% samples, and increases to 42 °C for 10 wt% samples. From variable temperature SAXS characterization micelles of 20–25 nm in radius can be seen and maintain their size and packing below 32 °C. A gradual increase in the aggregation of micelles corresponding to a thickening of the material is also observed. Close to and above the gelation temperature, micelles collapse and form a physically associated 3D network. A model is proposed to explain these physical effects, where the poly(vinyl caprolactam) group transitions from the hydrophilic corona at room temperature to the hydrophobic core as temperature is increased. 

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3. Effects of temperature on chaotropic anion-induced shape transitions of star molecular bottlebrushes with heterografted poly(ethylene oxide) and poly( N , N -dialkylaminoethyl methacrylate) side chains in acidic water

   https://doi.org/10.1039/D1SM00728A  

   Lewoczko, Evan M. ; Kelly, Michael T. ; Kent, Ethan W. ; Zhao, Bin ( July 2021 , Soft Matter)

   null (Ed.)

   This article reports a study of the effects of temperature on chaotropic anion (CA)-induced star-globule shape transitions in acidic water of three-arm star bottlebrushes composed of heterografted poly(ethylene oxide) (PEO) and either poly(2-( N , N -dimethylamino)ethyl methacrylate) (PDMAEMA) or poly(2-( N , N -diethylamino)ethyl methacrylate) (PDEAEMA) (the brushes denoted as SMB-11 and -22, respectively). The brush polymers were synthesized by grafting alkyne-end-functionalized PEO and PDMAEMA or PDEAEMA onto an azide-bearing three-arm star backbone polymer using the copper( i )-catalyzed alkyne-azide cycloaddition reaction. Six anions were studied for their effects on the conformations of SMB-11 and -22 in acidic water: super CAs [Fe(CN) 6 ] 3− and [Fe(CN)6] 4− , moderate CAs PF 6 − and ClO 4 − , weak CA I − , and for comparison, kosmotropic anion SO 4 2− . At 25 °C, the addition of super and moderate CAs induced shape transitions of SMB-11 and -22 in pH 4.50 water from a starlike to a collapsed globular state stabilized by PEO side chains, which was driven by the ion pairing of protonated tertiary amine groups with CAs and the chaotropic effect. The shape changes occurred at much lower salt concentrations for super CAs than moderate CAs. Upon heating from near room temperature to 70 °C, the super CA-collapsed brushes remained in the globular state, whereas the moderate CA-collapsed brushes underwent reversible globule-to-star shape transitions. The transition temperature increased with increasing salt concentration and was found to be higher for SMB-22 at the same salt concentration, presumably caused by the chaotropic effect. In contrast, I − and SO 4 2− had small effects on the conformations of SMB-11 and -22 at 25 °C in the studied salt concentration range, and only small and gradual size variations were observed upon heating to 70 °C. The results reported here may have potential uses in the design of stimuli-responsive systems for substance encapsulation and release. 

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4. Effect of Added Salt on Disordered Poly(ethylene oxide)- Block -Poly(methyl methacrylate) Copolymer Electrolytes

   https://doi.org/10.1021/acs.macromol.0c02493  

   Shah, Neel J. ; Dadashi-Silab, Sajjad ; Galluzzo, Michael D. ; Chakraborty, Saheli ; Loo, Whitney S. ; Matyjaszewski, Krzysztof ; Balsara, Nitash P. ( February 2021 , Macromolecules)

   null (Ed.)
5. The Chlamydia M278 Major Outer Membrane Peptide Encapsulated in the Poly(lactic acid)-Poly(ethylene glycol) Nanoparticulate Self-Adjuvanting Delivery System Protects Mice Against a Chlamydia muridarum Genital Tract Challenge by Stimulating Robust Systemic and Local Mucosal Immune Responses

   https://doi.org/10.3389/fimmu.2018.02369  

   Verma, Richa ; Sahu, Rajnish ; Dixit, Saurabh ; Duncan, Skyla A. ; Giambartolomei, Guillermo H. ; Singh, Shree R. ; Dennis, Vida A. ( October 2018 , Frontiers in Immunology)