Synthesis, Hydrophilicity and Micellization of Coil-Brush Polystyrene-b-(polyglycidol-g-polyglycidol) Copolymer-Comparison with Linear Polystyrene-b-polyglycidol.

Mariusz Gadzinowski,Barbara Trzebicka,Tomasz Makowski,Łukasz Otulakowski,Maciej Kasprów,Teresa Basinska,Stanislaw Slomkowski

doi:10.3390/polym14020253

Abstract

In this paper, an original method of synthesis of Coil-Brush amphiphilic polystyrene-b-(polyglycidol-g-polyglycidol) (PS-b-(PGL-g-PGL)) block copolymers was developed. The hypothesis that their hydrophilicity and micellization can be controlled by polyglycidol blocks architecture was verified. The research enabled comparison of behavior in water of PS-b-PGL copolymers and block–brush copolymers PS-b-(PGL-g-PGL) with similar composition. The Coil-Brush copolymers were composed of PS-b-PGL linear core with average DPn of polystyrene 29 and 13 of polyglycidol blocks. The DPn of polyglycidol side blocks of coil–b–brush copolymers were 2, 7, and 11, respectively. The copolymers were characterized by 1H and 13C NMR, GPC, and FTIR methods. The hydrophilicity of films from the linear and Coil-Brush copolymers was determined by water contact angle measurements in static conditions. The behavior of Coil-Brush copolymers in water and their critical micellization concentration (CMC) were determined by UV-VIS using 1,6-diphenylhexa-1,3,5-trien (DPH) as marker and by DLS. The CMC values for brush copolymers were much higher than for linear species with similar PGL content. The results of the copolymer film wettability and the copolymer self-assembly studies were related to fraction of hydrophilic polyglycidol. The CMC for both types of polymers increased exponentially with increasing content of polyglycidol.

Highlights

The synthesis of a set of PS-b-(PGL-g-PGL) coil–brush copolymers consisted of the following steps: (i) anionic polymerization of styrene yielding polystyrene macroinitiator with hydroxyl end-groups (PS-OH); (ii) anionic polymerization of glycidol with hydroxyl groups blocked with 1-ethoxyethyl moieties (GLB) yielding PS-b-PGLB copolymer; (iii) deprotection of hydroxyl groups in PGLB; (iv) synthesis of oligo-GLB grafts from alkoxide active centers formed on PGL block; and (v) deprotection of hydroxyl groups yielding PS-b(PGL-g-PGL)
The set of reactions involved in preparation of PS-b-(PGL-g-PGL) copolymer is presented in Scheme 2a,b
The images obtained from cryo-TEM revealed details of particles morphology

Summary

Introduction

Amphiphilic block copolymers (BCPs) have found numerous applications in various fields of science and branches of industry such as drug delivery carriers [1,2,3,4,5], bioactive agents carriers [6,7], tissue engineering materials [8], electrochemical sensors [9], polymer blends [10], polymer membranes [11], nanoreactors with embedded enzymes [12], enhanced-performance supercapacitors [13], anti-bacterial and anti-protein fouling coatings of various materials [14,15,16], surfactants systems for stabilization of various emulsions [17], and polymer solar cells [18]. The final application of copolymers is closely related to the chemical structure, architecture of macromolecules and properties of blocks components. Amphiphilic block copolymers undergo self-assembly, which very often leads to the formation of hierarchical periodic nanostructures. In spite of the same chemical composition, amphiphilic copolymers may significantly differ in architecture. The architecture affects copolymers organization in nano- or microstructures and impacts on their final application

Methods

Results

Conclusion