The Static Structure and Dynamics of Cadmium Sulfide Nanoparticles within Poly(styrene‐block‐isoprene) Diblock Copolymer Melts

Abstract

The static structure and dynamic behavior of cadmium sulfi de nanoparticles suspended in block copolymer matrix are investigated using transmission electron microscopy, small-angle X-ray scattering, and X-ray photon correlation spectroscopy. The transmission electron microscopy study shows that cadmium sulfi de nanoparticles are preferentially segregated within the polyisoprene domain of a poly(styrene-block -isoprene) diblock copolymer. For the dynamics study, X-ray photon correlation spectroscopy captures the relaxation process of cadmium sulfi de nanoparticles. The measured characteristic relaxation time reveals that the observed dynamics are hyperdiffusive. The characteristic velocity and corresponding activation energy, which are hallmarks of a hyperdiffusive system, are determined from the relationship between the characteristic relaxation time and the wavevector.the BCP provide a means to precisely control the spatial organization of the NPs. Theoretical investigations have suggested that a synergetic interaction between NPs and a self-organizing BCP matrix could produce hierarchically structured functional hybrid materials. [1][2][3] We refer to these nanocomposites as NP-BCPs. Such material design fl exibility is utilized to tune the electrical, [ 4 ] magnetic, [ 5 ] or biomedical [ 6 ] properties of targeted NP-BCPs. Despite recent progress on the fabrication techniques and contemporary applications of NP-BCPs, the equilibrium state and structural dynamics of these materials still remains poorly understood. This is in part because NP-BCPs compound the diffi culties caused by the entropic and enthalpic interactions between NPs and the BCP domain. In addition, many of the key methods for structural elucidation are less useful for characterizing dynamic behavior.The unique self-assembling features of the BCP can be used to synthesize NPs. Specifi cally, poly(styrene-block -2 vinylpyridine) (S2VP) or poly(styrene-block -4 vinylpyridine) (S4VP), which are solvent-selective diblock copolymers, provide a micellar structure for metal/semiconductor

Tailorable Micelle Morphology in Self-Assembling Block Copolymer Gels for Templating Nanoporous Ceramics

“…Block copolymers (BCPs) have become an important enabling material in the organization and fabrication of nanoscale patterns and features. Because of their ability to self-assemble, BCPs provide an attractive template material for nanoparticles − or other polymers. − BCPs’ tunable block–block interactions (via polymer composition and molecular weight) can be manipulated to create different well-defined, self-assembled nanostructured phases (e.g., columnar, lamella, and gyroid). − After organizing the desired templated material, BCP templates are easily removed through burnout, UV/ozone treatment, or selective solvent dissolution, depending on BCP composition and end application.…”