Molecular Dynamics and Self-Assembly in Double Hydrophilic Block and Random Copolymers.

Area of Science:

• Polymer Science
• Materials Chemistry
• Physical Chemistry

Background:

• Double hydrophilic block copolymers (DHBCs) offer tunable properties.
• Understanding the self-assembly and dynamics of DHBCs is crucial for material design.

Purpose of the Study:

• To investigate the self-assembly and molecular dynamics of DHBCs comprising POEGMA and PVBTMAC.
• To characterize the influence of block copolymer composition on material properties.

Main Methods:

• Calorimetry (DSC)
• Small- and wide-angle X-ray scattering (SAXS/WAXS)
• Dielectric spectroscopy

Main Results:

• X-ray measurements indicated weak segregation and a disordered state, suggesting inherent miscibility.
• Intermixed nanodomains led to homogeneous molecular dynamics with a glass transition 40 K higher than bulk POEGMA.
• Confined POEGMA segments exhibited reduced glass transition temperature, dielectric strength, broader relaxation times, and lower fragility.
• Two distinct glass transition temperatures were observed for dry PVBTMAC, attributed to backbone and side-chain relaxation.

Conclusions:

• Excellent miscibility was achieved between POEGMA and PVBTMAC blocks.
• The properties of these DHBCs can be precisely tailored by adjusting the homopolymer concentrations.
• This work provides novel insights into the glass transitions of dry PVBTMAC.