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Gold nanoparticles functionalized with block copolymers displaying either LCST or UCST thermosensitivity in aqueous
1Departement de chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 8, 2010
Summary
Researchers developed polymer-coated gold nanoparticles (AuNPs) with tunable thermosensitivity. These nanoparticles exhibit controlled solubility changes, preventing aggregation in aqueous solutions via stimuli-responsive polymer chains.
Area of Science:
- Materials Science
- Nanotechnology
- Polymer Chemistry
Background:
- Gold nanoparticles (AuNPs) are widely studied for their unique optical and electronic properties.
- Controlling nanoparticle dispersion and stability in aqueous solutions is crucial for their applications.
- Thermosensitive polymers offer tunable solubility, enabling stimuli-responsive material behavior.
Purpose of the Study:
- To synthesize gold nanoparticles coated with poly(ethylene oxide)-block-poly(N,N-dimethylaminoethyl methacrylate) (PEO-b-PDMAEMA) diblock copolymers.
- To investigate the thermosensitive behavior (LCST and UCST) of these polymer-coated AuNPs in aqueous solutions.
- To explore the photothermal effect on the solubility and dispersion stability of the functionalized AuNPs.
Main Methods:
- Synthesis of PEO-b-PDMAEMA diblock copolymers and their grafting onto gold nanoparticles.
- Quaternization of PDMAEMA chains using 1,3-propane sultone.
- Fluorescence spectroscopy using pyrene as a probe to monitor polymer solubility and nanoparticle aggregation.
- Temperature and light (near SPR band) stimuli to induce reversible solubility changes.
Main Results:
- Polymer-coated AuNPs exhibited thermally induced solubility changes, showing either Lower Critical Solution Temperature (LCST) or Upper Critical Solution Temperature (UCST) behavior.
- The poly(ethylene oxide) (PEO) outer block effectively prevented AuNP aggregation during solubility transitions.
- Reversible solubility changes were induced by both temperature and light irradiation near the AuNP surface plasmon resonance band, indicating a photothermal effect.
Conclusions:
- A facile method for preparing polymer-coated AuNPs with tunable LCST or UCST thermosensitivity was established.
- The developed AuNPs maintain stable aqueous dispersion under stimuli-responsive solubility changes.
- The findings offer a versatile platform for creating smart nanomaterials with potential applications in drug delivery and sensing.
