Wei Liu

Raman spectroscopy has been widely used in the recent development of semiconductor, energy storage and quantum materials, high speed and high resolution confocal Raman imaging provides extremely valuable material information. Newly launched witec 360 with Hexalight spectrometer brings a few spectroscopic technologies into one integrated solution, including but not limited to Raman, PL and SHG imaging capabilities, which enables a comprehensive, non‑destructive characterization workflow for material studies. In this presentation, system configuration will be introduced and a number of application will be discussed to show case these capabilities.

Kate Kiseeva

TBD

Cheryl Yao

Airborne microplastics (MPs) are emerging contaminants of concern because of their potential impacts on human health and their contribution to pollution in water, soil, and sediment. This study investigated the distribution, composition, and morphology of airborne microplastics in indoor and ambient air in northern New Jersey, USA. Microplastic fibers, films, and fragments composed of polystyrene (PS), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) were identified in offices, hallways, classrooms, and a single-family house. The deposition rates of synthetic fibers, ranging from 35 µm to 1000 µm in length, were highest in the single-family house and lowest in the classroom, suggesting that residential environments may be important sources of airborne microplastic fibers. In contrast, film-like microplastics with surface areas of 200-5000 µm2 showed the highest deposition rate in the classroom and the lowest in the hallway, likely reflecting intensive use of plastic film materials in classroom settings. The deposition rate of microplastics in ambient air collected on a building roof was only about 2-8% of indoor deposition rates. Microplastics with similar textures but different sizes were identified in both total atmospheric deposition and particulate samples (PM2.5 and PM10), suggesting ongoing fragmentation from microplastics to smaller particles, potentially including nanoplastics. PE particles and fibers dominated indoor air samples, whereas PVC fragments were more prevalent in outdoor ambient air. Overall, these findings provide new insight into the characteristics of airborne microplastics in urban environments and improve our understanding of their sources, transport, fate, and potential health risks.

Ted Limpoco

We have developed the first commercial atomic force microscope to use quadrature phase differential interferometry (QPDI) which greatly improves the accuracy and precision of AFM measurements. This is not the first AFM to use interferometric sensing. Several early implementations were abandoned because of their complexity, limited measurement range, and poor low-frequency noise performance. When optical beam deflection (OBD) was introduced in 1988, it became the standard AFM detection system until today.​

St. John

An estimated 1/3 of molecular crystals can be prompted to grow as banded spherulites, which are polycrystalline aggregates of helical fibers. Between glass slides, banded spherulites form as thin films which expose different crystallographic facets at the film-air interface along the fiber helical axis. The crystalline anisotropic properties are therefore patterned, which include refractive index, absorbance, fluorescence, conductivity, and solubility, to name a few. Three separate projects are discussed which revolve around the usage of an Asylum atomic force microscope (AFM) to probe the chiral structures present in banded spherulite films. Because the twisting pitch of the helical crystals is variable and controllable, AFM is well-suited to probe these systems. AFM can map the spatial distribution of properties, ultimately allowing for correlation between crystalline orientation and a corresponding anisotropic property. Three unique applications will be discussed which range from nanoscopic interfacial facet measurements, conductivity measurement in thin films, and a custom photoconductivity module.

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