The Importance of Cooperativity in Polymer Blending: Toward Controlling the Thermoresponsive Behavior of Blended Block Copolymer Micelles

Abstract

Understanding, predicting, and controlling the self‐assembly behavior of stimuli‐responsive block copolymers remains a pertinent challenge. As such, the copolymer blending protocol provides an accessible methodology for obtaining a range of intermediate polymeric nanostructures simply by blending two or more block copolymers in the desired molar ratio to target specific stimuli‐responsiveness. Herein, thermoresponsive diblock copolymers are blended in various combinations to investigate whether the resultant cloud point temperature can be modulated by simple manipulation of the molar ratio. Thermoresponsive amphiphilic diblock copolymers composed of statistical poly(n‐butyl acrylate‐co‐N,N‐dimethylacrylamide) core‐forming blocks and four different thermoresponsive corona‐forming blocks, namely poly(diethylene glycol monomethyl ether methacrylate) (p(DEGMA)), poly(N‐isopropylacrylamide), poly(N,N‐diethylacrylamide), and poly(oligo(ethylene glycol) monomethyl ether methacrylate) (p(OEGMA)) are selected for evaluation. Using variable temperature turbidimetry, the thermoresponsive behavior of blended diblock copolymer self‐assemblies is assessed and compared to the thermoresponsive behavior of the constituent pure diblock copolymer micelles to determine whether comicellization is achieved and more significantly, whether the two blended corona‐forming thermoresponsive blocks exhibit cooperative behavior. Interestingly, blended diblock copolymer micelles composed of p(DEGMA)/p(OEGMA) mixed coronae display cooperative behavior, highlighting the potential of copolymer blending for the preparation of stimuli‐responsive nanomaterials in applications such as oil recovery, drug delivery, biosensing, and catalysis.

Thermo‐responsive block copolymer micelle‐supported (S)‐α,α‐diphenylprolinol trimethylsilyl ether for asymmetric Michael addition of nitroalkenes and aldehydes in water

“…Thermo‐responsive behavior of diblock copolymers was also measured by the temperature‐variable UV–vis spectroscopy 29,30 . It was observed that the transmittance of copolymer solutions changed during heating.…”

Polymers Blending as Release Modulating Tool in Drug Delivery

“…In this regard, surface adsorption of the drug to the PLGA block copolymer could result in 60-70% initial burst release (Mohammadi-Samani and Taghipour, 2015). Copolymer blending is a type of polymer blending approach in which two or more block copolymers with different characteristics, functionalities, and stimuli-responsiveness are mixed in order to form a unique polymer blend with special characteristics (Keogh et al, 2020). It has been reported that recruitment of albumin in the synthesis of block copolymers could affect drug release profile from hydrogels, while the gel consistency of the fabricated block copolymer was reduced (Perinelli et al, 2014).…”

“…Among the different types of polymeric materials as drug carrier, stimuli-responsive polymers are considered attractive polymeric carriers which undergo phase transitions in response to different environmental stimuli including temperature, pH, light, and enzymes. (Keogh et al, 2020). Thermo-responsive polymers are a common type of smart or stimuli-responsive polymeric carrier that show a change in solubility at a point called critical solution temperature (CST) (Ward and Georgiou, 2011).…”

“…Most of these delivery systems are block copolymer with unique characteristics. Polymeric blends and different approaches of polymer blending could significantly affect this CST and tune the drug release profile for drug delivery purposes (Keogh et al, 2020). For biomedical applications, the trigger to form thermo-responsive hydrogels would be the change in temperature from environment to physiologic condition which is called in situ hydrogel formation (Klouda, 2015).…”

Utilizing Stimuli Responsive Linkages to Engineer and Enhance Polymer Nanoparticle-Based Drug Delivery Platforms

“…The concentration of the various polymers in this mixture can then be altered so that the T cp falls in the temperature range of tumors and outside of that of healthy cells. 75 Zhang et al engineered a tetrablock copolymer containing three thermoresponsive blocks: poly(polyethylene glycol methacrylate) (PPEGMA), PDMAEMA, and PNI-PAM. 30 An initial PPEGMA-PDMAEMA chain was linked to a PNIPAM block to make the LCST of the micelles formed consistent with the temperature of the body.…”