Revisiting crosslinking density effects on pNIPAM microgel properties: Size, electrophoretic mobility, and transition...

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Poly(N-isopropylacrylamide) (pNIPAM) microgels are thermoresponsive materials with applications in drug delivery, tissue engineering, and sensors.
• The relationship between crosslinking density and pNIPAM microgel properties is complex and requires further investigation for optimized material design.
• Understanding how crosslinking density influences electrokinetic properties and transition temperatures is crucial for advanced applications.

Purpose of the Study:

• To elucidate the relationship between crosslinking density and the size and electrophoretic mobility of pNIPAM microgels.
• To examine the influence of crosslinking density on transition temperatures, with a focus on the electrokinetic transition temperature.
• To provide a pathway for the rational design of pNIPAM microgels tailored for specific applications.

Main Methods:

• Synthesis of 20 batches of pNIPAM microgels using conventional one-pot and semi-batch methods with varying crosslinking densities.
• Characterization using dynamic light scattering (DLS) for size and thermoresponsive behavior.
• Electrophoretic light scattering (ELS) for electrophoretic mobility, and atomic force microscopy (AFM) for morphology and stiffness.

Main Results:

• Established clear relationships between crosslinking density and pNIPAM microgel size and electrophoretic mobility.
• Investigated the impact of crosslinking density on transition temperatures, including the electrokinetic transition temperature.
• Demonstrated how crosslinking density dictates the physical and electrokinetic properties of pNIPAM microgels.

Conclusions:

• Crosslinking density is a critical parameter for tuning the thermoresponsive behavior and electrokinetic properties of pNIPAM microgels.
• The findings provide a foundation for designing pNIPAM microgels with specific characteristics for targeted applications.
• This study enhances the understanding of pNIPAM microgel behavior, facilitating their development in advanced technological fields.