@article{schmitz_wohl_tiemsin_genzer_2020, title={Controlled heating and alignment platform enhances versatility in colloidal probe fabrication}, volume={91}, ISSN={["1089-7623"]}, DOI={10.1063/1.5111387}, abstractNote={A colloidal probe, comprising a colloidal particle attached to an atomic force microscope cantilever, is employed to measure interaction forces between the particle and a surface. It is possible to change or even destroy a particle while attaching it to a cantilever, thus limiting the types of systems to which the colloidal probe technique may be applied. Here, we present the Controlled Heating and Alignment Platform (CHAP) for fabricating colloidal probes without altering the original characteristics of the attached particle. The CHAP applies heat directly to the atomic force microscope chip to rapidly and precisely control the cantilever temperature. It minimizes particle heating and enables control over the viscosity of the thermoplastic adhesive to prevent it from contaminating the particle surface. 3D-printed components made the CHAP compatible with standard optical microscopes and streamlined the fabrication process, while increasing the platform's versatility. To demonstrate the utility of CHAP, we conducted a case study using a thermoplastic wax adhesive to fabricate colloidal probes bearing polystyrene and silica particles between 0.7 and 40 μm in diameter. We characterized the properties and interactions of the adhesive and particles, as well as the properties of the completed probes, to demonstrate the retention of particle features throughout fabrication. Pull-off tests with CHAP's probes measured adhesive force values in the expected ranges and demonstrated that particles were firmly attached to the cantilevers.}, number={1}, journal={REVIEW OF SCIENTIFIC INSTRUMENTS}, author={Schmitz, Russell C. and Wohl, Christopher J. and Tiemsin, Pacita I. and Genzer, Jan}, year={2020}, month={Jan} }
 @article{applin_schmitz_tiemsin_genzer_connell_wohl_2017, title={Further insight into the mechanism of poly(styrene-co-methyl methacrylate) microsphere formation}, volume={55}, ISSN={["1099-0518"]}, DOI={10.1002/pola.28612}, abstractNote={Polymeric microspheres have been utilized in a broad range of applications ranging from chromatographic separation techniques to analysis of air flow over aerodynamic surfaces. The preparation of microspheres from many different polymer families has consequently been extensively studied using a variety of synthetic approaches. Although there are a variety of methods of synthesis for polymeric microspheres, free-radical initiated emulsion polymerization is one of the most common techniques. In this work, poly(styrene-co-methyl methacrylate) microspheres were synthesized via surfactant-free emulsion polymerization. The effect of co-monomer composition and addition time on particle size distribution, particle formation, and particle morphology were investigated. Particles were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM) to gain further insight into particle size and size distributions. Reaction kinetics were analyzed alongside of characterization results. A particle formation mechanism for poly(styrene-co-methyl methacrylate) microspheres was proposed based on characterization results and known reaction kinetics.}, number={13}, journal={JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY}, author={Applin, Samantha I. and Schmitz, Russell C. and Tiemsin, Pacita I. and Genzer, Jan and Connell, John W. and Wohl, Christopher J.}, year={2017}, month={Jul}, pages={2249–2259} }