가교된 PNIPAAm 표면층을 가지는 온도응답성 실리카 나노입자의 제조 및 특성분석 = Preparation and Characterization of Thermo-Responsive Silica Nanoparticles with Cross-linked PNIPAAm Shell Layers

다국어 초록 (Multilingual Abstract)

In this study, we prepared organic-inorganic hybrid nanoparticies with a core-shell structure using a surface-initiated polymerization technique. Initiators for the atom transfer radical polymerization were anchored onto the surface of silica nanoparticies, and from there N-isopropylacrylamide and methylene bisacrylamide were polymerized to form cross-linked polymeric shell layers. The thickness of the polymer layers was controlled by varying the reaction time. The thermal phase transition of the surface polymer layer was characterized by dynamic light scattering analysis, which showed reversible swelling/deswelling behavior between $25^{\circ}C$ and $40^{\circ}C$. Compared to the silica nanoparticies with linear polymer layers, the swelling/deswelling behavior was of a smaller degree, but it consistently exhibited similar size changes after repeated processes. HF etching of the silica nanoparticies with surface cross-linked polymer layers removed the silica core to render a hollow structure.

참고문헌 (Reference)

1 J. J. Storhoff, "What Controls the Optical Properties of DNA-Linked Gold Nanoparticle Assemblies" 122 : 4640-4650, 2000

2 J. Shan, "Two Phase Transitions of Poly(N-isopropylacrylamide) Brushes Bound to Gold Nanoparticles" 20 : 4671-4676, 2004

3 C. Perruchot, "Synthesis of Well-Defined, Polymer-Grafted Silica Particles by Aqueous ATRP" 17 : 4479-4481, 2001

4 J. Pyun, "Synthesis of Well-Defined Block Copolymers Tethered to Polysilsesquioxane Nanoparticles and Their Nanoscale Morphology on Surfaces" 123 : 9445-9446, 2001

5 O. Prucker, "Synthesis of Poly(styrene) Monolayers Attached to High Surface Area Silica Gels through Self-Assembled Monolayers of Azo Initiators" 31 : 592-601, 1998

6 J. Pyun, "Synthesis and Characterization of Organic/ Inorganic Hybrid Nanoparticles: Kinetics of Surface-Initiated Atom Transfer Radical Polymerization and Morphology of Hybrid Nanoparticle Ultrathin Films" 36 : 5094-5104, 2003

7 X. Y. Chen, "Synthesis and Aqueous Solution Properties of Polyelectrolyte-Grafted Silica Particles Prepared by Surface-initiated Atom Transfer Radical Polymerization" 257 : 56-64, 2003

8 T. Teranishi, "Size Control of Palladium Nanoparticles and Their Crystal Structures" 10 : 594-600, 1998

9 T. von Werne, "Preparation of Structurally Well-Defined Polymer-Nanoparticle Hybrids with Controlled/ Living Radical Polymerizations" 121 : 7409-7410, 1999

10 D. E. Bergberiter, "Poly(N-isopropylacrylamide) Soluble Polymer Supports in Catalysis and Synthesis" 31 : 6053-6062, 1998

11 F. Caruso, "Nanoengineering of Particle Surfaces" 13 : 11-22, 2001

12 J. H. Golden, "Monodisperse Metal Clusters 10 Angstroms in Diameter in a Polymeric Host: The ‘Monomer as Solvent’ Approach" 268 : 1463-1466, 1995

13 H. Mori, "Hybrid Nanoparticles with Hyperbranched Polymer Shells via Self-Condensing Atom Transfer Radical Polymerization from Silica Surfaces" 18 : 3682-3693, 2002

14 M. C. Daniel, "Gold Nanoparticles: Assembly, Supramolecular Chemistry, Quantum-Size-Related Properties, and Applications Toward Biology, Catalysis, and Nanotechnology" 104 : 293-346, 2004

15 T. Wu, "Fabrication of Hybrid Silica Nanoparticles Densely Grafted with Thermoresponsive Poly(N-isopropylacrylamide) Brushes of Controlled Thickness via Surface-Initiated Atom Transfer Radical Polymerization" 20 : 101-109, 2008

16 D. J. Li, "Environmentally Responsive “Hairy” Nanoparticles: Mixed Homopolymer Brushes on Silica Nanoparticles Synthesized by Living Radical Polymerization Techniques" 127 : 6248-6256, 2005

17 E. Bourgeat-Lami in, "Encyclopedia of Nanoscience and Nanotechnology" Scientific Publishers 305-, 2004

18 G. Carrot, "Atom Transfer Radical Polymerization of n-Butyl Acrylate from Silica Nanoparticles" 39 : 4294-4301, 2001

19 T. von Werne, "Atom Transfer Radical Polymerization from Nanoparticles: A Tool for the Preparation of Well-Defined Hybrid Nanostructures and for Understanding the Chemistry of Controlled/“Living” Radical Polymerizations from Surfaces" 123 : 7497-7505, 2001

20 D. L. Klein, "A Single-Electron Transistor Made from a Cadmium Selenide Nanocrystal" 389 : 699-701, 1997