Synthesis and temperature-induced self-assembly of a positively charged symmetrical pentablock terpolymer in aqueous solutions

Dissipative Particle Dynamics Simulation for the Self-Assembly of Symmetric Pentablock Terpolymers Melts under 1D Confinements

The phase behavior of CBABC pentablock terpolymers confined in thin films is investigated using the Dissipative Particle Dynamic method. Phase diagrams are constructed and used to reveal how chain length (i-block length), block composition and wall selectivity influence the self-assembly structures. Under neutral walls, four categories of morphologies, i.e., perpendicular lamellae, core-shell types of microstructures, complex networks, and half-domain morphologies, are identified with the change in i-block length. Ordered structures are more common at weak polymer-polymer interaction strengths. For polymers of a consistent chain length, when one of the three components has a relatively smaller length, the morphologies transition is sensitive to block composition. With selective walls, parallel lamellae structures are prevalent. Wall selectivity also impacts chain conformations. While a large portion of chains form loop conformations under A-selective walls, more chains adopt bridge conformation when the wall prefers C-blocks. These findings offer insights for designing nanopatterns using symmetric pentablock terpolymers.

Synthesis and Characterization of Gamma Radiation Induced Diallyldimethylammonium Chloride-Acrylic Acid-(3-Acrylamidopropyl) Trimethylammonium Chloride Superabsorbent Hydrogel

The gamma radiation technique is simple and time-saving for the synthesis of pure hydrogels. The present work focuses on synthesizing and characterizing Diallyldimethylammonium Chloride-Acrylic acid-(3-Acrylamidopropyl) trimethylammonium Chloride (DADMAC-AAc-APTAC) superabsorbent hydrogels. The hydrogels were synthesized by applying gamma radiation of different doses (2 kGy to 30 kGy) to two different compositions of monomers. The equilibrium swelling was found to be 33483.48% of dried gel for a 1:0.5:1 composition ratio of monomers at a 2 kGy radiation dose. Therefore, on the basis of equilibrium swelling, 2 kGy is the optimum radiation dose for synthesizing the hydrogel. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, and X-ray diffraction (XRD) characterization techniques were used to analyze and confirm the structure of the hydrogel. Thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) clearly showed the thermal stability and surface morphology of the gel. Therefore, it can be concluded that hydrogels can be used in metal adsorption, drug delivery, and other fields of study.

Self-Assembly Behavior of Elastin-like Polypeptide Diblock Copolymers Containing a Charged Moiety

Elastin-like polypeptides (ELPs) are stimulus-responsive protein-based biopolymers, and some ELP block copolymers can assemble into spherical nanoparticles with thermosensitivity. In this study, two different ELP diblock copolymers, each composed of a hydrophobic and a charged moiety, were synthesized, and the dependence of their physical properties on pH, temperature, and salt concentration was investigated. A series of analyses revealed that hydrophobic core micelles could be generated in response to a change in their surroundings and that micelles did not self-aggregate, a phenomenon due to the repulsive forces between like-charged molecules on the surface. We also demonstrated that self-assembly behavior was closely dependent on the character of the charged amino acid and the specific anion in solution.