Thermoresponsive Diblock Copolymer with Tunable Soluble–Insoluble and Soluble–Insoluble–Soluble Transitions

Abstract

The thermoresponsive transition behavior of a diblock copolymer consisting of poly(ethylene glycol) methyl ether (mPEG) and poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) in aqueous solutions has been investigated. With a specific composition, the copolymer showed a unique tunable phase transition from no response in acidic media to a soluble-insoluble (S-I) transition in neutral media and an S-I-S transition in basic media either in the presence of salt or for salt-free solutions. The S-I-S transition can be tuned over a wide temperature range even to an S-I type transition just by adding salts. In addition, phase transitions can occur in both pure water and saline solution under practical conditions (30-80 °C), which makes them suitable for a broad range of applications.

Thermo-responsive block copolymers with multiple phase transition temperatures in aqueous solutions

“…The block length-dependent packing of micelles leading to gelation has been described in detail for example for thermo-responsive poly(oxyethylene)-b-poly(oxybutylene) diblock copolymers in water, although such systems exhibit only a single sol-to-gel transition that depends on polymer concentration [136]. The packing of micelles is analogous to the arrangement of sterically stabilized or charge-stabilized colloidal particles (hard or soft spheres) into colloidal crystalline arrays [137] M a n u s c r i p t PTEGSt (PTEGSt = poly(4-vinylbenzyl methoxytris(oxyethylene) ether)) [161], proline-based block copolymers [162,163], and PDMAEMA-based systems [164]. block, respectively) showed LCST behavior in their native state and UCST behavior after the quaternization into a sulfobetaine, both in aqueous solutions [166].…”

Modeling Swelling Behavior of Thermoresponsive Polymer Brush with Lattice Density Functional Theory

“…[ , ] [ , ] inter s m am s m ac s m (14) The expressions of the two functions, f inter for the attractive interactions and f ac for the coupling effects, can be obtained through the Helmholtz energy for uniform fluids, (16) where ε̃represents the attraction interactions between the nearest-neighbor sites, which is a reduced exchange energy, ε̃= (ε/kT) = [(ε pp + ε ss − 2ε ps )/kT] between segment p and solvent s, where ε ij is the attractive energy of the i−j pair. And λ is a factor accounting for the long-range correlations of polymers defined as…”

Multi-stimuli-responsive semi-IPN cryogels with native and anionic potato starch entrapped in poly(N,N-dimethylaminoethyl methacrylate) matrix and their potential in drug delivery

“…As reported in literature, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEM) is a polycation endowed with antibacterial, hemostatic and anticancer properties [13,14], which has been used in the preparation of new drug or gene delivery systems [15]. PDMAEM is a weak polybase bearing tertiary amine groups with a pk a located at around 7.0 [8], which showed a pHdependent lower critical solution temperature (LCST) [16], and a upper critical solution temperature (UCST) in the presence of multivalent counterions [17]. The LCST of PDMAEM, which in aqueous solution at neutral pH is located at around 50°C, is much higher than the human body temperature but could be modulated by copolymerization of DMAEM with more hydrophobic moieties, such as NIPAAm [18][19][20][21], or 2-(2-methoethoxyethyl methacrylate) [22].…”

“…Due to the reversible swelling/shrinkage capacity, these materials have been explored in the last decade for various technological and biomedical applications, such as sensors, separations, drug delivery systems, cartilage, artificial muscles, and actuators. The interest in finding novel biocompatible polymers, which could respond to two or more external stimuli, is growing and therefore various types of such polymers have been prepared in the last decade [7][8][9][10][11][12]. As reported in literature, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEM) is a polycation endowed with antibacterial, hemostatic and anticancer properties [13,14], which has been used in the preparation of new drug or gene delivery systems [15].…”