Study On The Properties Of Amphiphilic Polymer Brushes Melts And Solutions

Amphiphilic polymer brushes are a type of polymer system formed by grafting two types of hydrophilic/hydrophobic polymers or small molecules onto the polymer backbone.Their surface properties and functions can be precisely tuned by adjusting their structural parameters such as hydrophilic/hydrophobic ratios,side chain length and grafting density,etc.This paper aims to establish the relationship between the structural parameters and properties of amphiphilic polymer brushes,explore their melt rheology,adhesion,solution assembly characteristics through systematic adjustment of topological structure parameters,and study their potential application in high-performance adhesive materials.The main research results include:（1）In this study,a series of amphiphilic polymer brushes PNB-g-（PEO-co-C₆）were synthesized by copolymerization of NB-PEO and NB-C₆ monomers with different molar ratios and total monomer-to-catalyst ratios,where NB-PEO served as the side chain and NB-C₆ as the spacer.The main chain degree of polymerization,side chain degree of polymerization,and side chain molar fraction of PEO were systematically adjusted to explore the effect of topological structure parameters on the linear rheological behavior of the polymer brush melts.It was found that polymers with longer side chains and higher main chain degrees of polymerization,as well as lower side chain density,had enhanced terminal relaxation times and zero shear viscosity.Additionally,the existence of the microphase separation significantly delayed chain relaxation,leading to an increase in both terminal relaxation time and zero shear viscosity.（2）This study investigated the effect of topological structure parameters on the nonlinear adhesive behavior of PNB-g-（PEO-co-C₆）polymer brush melts.It was found that by optimizing the topological structure parameters,the amphiphilic polymer brush melt exhibited good adhesion performance on various substrate materials.The influence of structural parameters on both linear rheological and nonlinear adhesive behavior was found to be equivalent,meaning that longer terminal relaxation time and higher zero shear viscosity resulted in stronger adhesive properties.The adhesive behavior of the amphiphilic polymer brush melts was primarily affected by viscoelastic energy dissipation,while its nonlinear adhesive behavior was controlled by polymer chain dynamics,independent of structural parameters,testing strain rate,and environmental temperature.（3）This study explored the self-assembly behavior of PNB-g-（PEO-co-C₆）amphiphilic polymer brushes in aqueous solution.Various in-situ characterization techniques such as small-angle neutron scattering,small-angle X-ray scattering,and nuclear magnetic resonance were used to investigate their behavior.It was found that with increasing polymer concentration,the comb polymer micelles formed a layered structure along the length direction of the cylindrical body,while bottlebrush polymer micelles experienced intramolecular bending or folding.In aqueous solution,the assembly shape of polymer brushes could be well described using a core-shell cylindrical structure,where the assembly size increased with increasing values of structural parameters9)₍（7（7）,9）_（8）,and1.Moreover,during temperature variation,the polymer brush solution underwent a phase transition.Before the transition,the solvent was excluded from the shell structure,and the PEO chain entered the core structure,causing the polymer chains to aggregate.After the transition,the assembly size rapidly decreased,and the compact structure resulted in stronger correlations between adjacent assemblies.