Temperature/pH‐Sensitive Hydrogels Prepared from Pluronic Copolymers End‐Capped with Carboxylic Acid Groups via an Oligolactide Spacer

Abstract

The Pluronic F127 triblock copolymer was end‐capped by carboxyl groups using a degradable oligolactide as a spacer to confer pH‐ and thermo‐sensitive properties. With increasing chain length of the oligolactide, the temperature‐dependent sol‐gel transition curve was significantly shifted to higher concentration with concomitant narrowing of the gelation temperature range. Carboxylic acid end‐capped Pluronic also exhibited a peculiar pH‐dependent sol‐gel transition behavior. At 37 °C, sharp gel‐to‐sol and sol‐to‐gel transitions were observed around pH = 4.8 and 8.2, respectively. The pH‐dependent phase transition was caused by introduction of carboxylic acid groups at the ends of Pluronic F127.magnified image

Stimuli responsive associative polyampholytes based on ABCBA pentablock terpolymer architecture

“…These differences should be ascribed to the nature of the network elastic chains and mainly to the considerably longer length (arisen from electrostatic stretching) in high pH (PAA 355 -P2VP-PAA 355 ) with respect to that in low pH (PAA-P2VP 296 -PAA). It should be mentioned here that in both type of gels the observed critical gel concentration is significantly lower than those of other non-ionic ABCBA associative polymers reported recently [54][55][56][57].…”

Synthesis and Characterization of a Multi‐Sensitive Crosslinked Injectable Hydrogel Based on Pluronic

“…The results indicate that the sol‐gel phase transition curve of P‐B and CCP2 shifted slightly to the left and P‐A shifted to the right at same concentration compared to the Pluronic. Typically, gelation temperature of P‐A was probably caused by partitioning a relatively hydrophobic aromatic group existing π‐π interaction into the PPO core, disturbing the micellar integrity as well as packing density, it will affect the gelation temperature 30, 31. However, it was found from the investigation that CPP1 was shifted significantly to the left with a broadened gelation temperature window.…”

Direct Ink Writing Glass: A Preliminary Step for Optical Application

“…The gel is formed because of the increasing volume of the micelles and repulsive forces between them [21]. In previous studies, Bromberg et al [22] and Park et al [23] reported that Pluronic hydrogels are kept stable even when the pH of the solution is changed. On the basis of this data, it is assumed that the ionic strength insensitivity of the Pluronic F-127 hydrogel-based suspensions confers good stability to their rheological properties, thus facilitating the printing of water-sensitive glass materials.…”