title: Influence of microgel packing on raspberry-like heteroaggregate assembly.
abstract: We describe the influence of microgel packing on colloidal-phase mediated heteroaggregation using poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide) microgels with 1% mol or 5% mol N,N'-methylenebis(acrylamide) cross-linker. This system is uniquely designed to interrogate the influence of microgel structure and stiffness on microgel deformation at a curved interface by elminating the necessity of electrostatic charge pairing. Microgel monomer and cross-linker content is expected to influence deformation at a curved interface. Microgel deformation and swelling were characterized via atomic force microscopy (AFM) and viscometry. A systematic study of colloidal-phase mediated heteroaggregation was performed at varied effective volume fractions with all microgel compositions. Scanning electron microscopy (SEM) and qNano pore translocation experiments were used to asses the microgel coverage on the resultant raspberry-like particles (RLPs). Results reveal that microgel composition has a strong influence on the efficiency (as determined by microgel coverage) of RLP fabrication. The compositional effects appear to be related to the degree of microgel spreading/deformation at the interface, which is coupled to the influence of packing on assembly fidelity. These findings are widely applicable to systems where microgel deformation occurs at a curved interface. We also demonstrate that qNano pore translocation experiments can be used as a high-throughput method to analyze RLP microgel coverage.
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, GA 30332, United States. Electronic address: ssaxena30@gatech.edu.
authors.forename: Shalini
authors.initials: S
authors.lastname: Saxena
authors.affiliation: Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States; Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, United States. Electronic address: lyon@chapman.edu.
authors.forename: L Andrew
authors.initials: LA
authors.lastname: Lyon
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D005782:Gels / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D003102:Colloids; D003432:Cross-Linking Reagents; D005782:Gels; D008689:Methacrylates; C052970:poly-N-isopropylacrylamide
keywords: Core–shell microparticles; Heteroaggregation; Microgel network structures