Quantifying Surface Area of Nanosheet Graphene Oxide Colloid Using a Gas-Phase Electrostatic Approach

Abstract

We demonstrate a new, facile gas-phase electrostatic approach to successfully quantify equivalent surface area of graphene oxide (GO) colloid on a number basis. Mobility diameter (d)-based distribution and the corresponding equivalent surface area (SA) of GO colloids (i.e., with different lateral aspect ratios) were able to be identified by electrospray-differential mobility analysis (ES-DMA) coupled to a condensation particle counter (CPC) and an aerosol surface area analyzer (ASAA). A correlation of SA ∝ d was established using the ES-DMA-CPC/ASAA, which is consistent with the observation by the 2-dimensional image analysis of size-selected GOs. An ultrafast surface area measurement of GO colloid was achieved via a direct coupling of ES with a combination of ASAA and CPC (i.e., measurement time was 2 min per sample; without size classification). The measured equivalent surface area of GO was ∼202 ± 7 m g, which is comparable to Brunauer-Emmett-Teller (BET) surface area, ∼240 ± 59 m g. The gas-phase electrostatic approach proposed in this study has the superior advantages of being fast, requiring no elaborate drying process, and requiring only a very small amount of sample (i.e., <0.01 mg). To the best of our knowledge, this is the first study of using an aerosol-based electrostatic coupling technique to obtain the equivalent surface area of graphene oxide on a number basis with a high precision of measurement.

Carbon based nanomaterials for tissue engineering of bone: Building new bone on small black scaffolds: A review

“…Because of the presence of oxygen, GO is more hydrophilic than pure G, and can more easily disperse in organic solvents, water, and different matrices [23], [24]. Recently, basic studies on the physicochemical properties GO, have shown that the hydrophilicity [25], mechanical strength [26], high surface area [27] and adhesive forces [28] are related to how the G sheets interact with each other. This interaction can occur by π-π stacking of [29], electrostatic or ionic interactions, and van der Waals forces depending on the exact structure of the functionalized sheets.…”

Real-Time Quantifying Microdroplet Synthesis of Metal–Organic Framework Colloids Using Gas-Phase Electrophoresis

“…After exiting the electrospray aerosol generator, the MOF aerosols with a neutralized charge distribution were delivered to an electrostatic classifier (model 3081, TSI Inc.) for size classification. An entire mobility size distribution can be obtained by varying the electric field applied to the electrostatic classifier (i.e., determined on the basis of the force balance between the electrostatic and the drag forces exerting on an aerosol particle). − The number concentration of aerosol particles with a specific mobility diameter ( d p,m ) was counted by using a n-butanol-based condensation particle counter (CPC, model 3775, TSI Inc.). − A sheath air flow rate ( Q sheath ) of 10.0 L/min was used for delivering aerosol particle downstream in the electrostatic classifier, and the step size and the step time used in the mobility size measurements were 2.0 nm and 5.0 s, respectively. Additional descriptions of the system design are shown in Section S1 of the Supporting Information.…”

“…Q aerosol and Q L are the filtered air flow (1.5 L/min) and the liquid flow through 40-μm fused silica capillary (i.e., estimated to be 4.3 × 10 −7 L/min). 23,24 Here, d p,m,max and d p,m,min are the maximum and the minimum values of the d p,m bounding to the peak of the analyzed population, respectively. dd p is the size increment in correspondence to the selected d p,m .…”

“…A flowing-mode electrospray-differential mobility analysis (ES-DMA) is established to hyphenate with the developed microdroplet synthetic system for providing a real-time high-resolution quantitative analysis of the continuously produced MOF colloid. Former studies have demonstrated the success of using stand-alone ES-DMA for the study of colloidal materials in batch synthesis/storage conditions, where physical size, colloidal stability (aggregation, disassembly, and dissolution), and size growth of the colloidal materials can be characterized quantitatively by analyzing the changes of mobility diameter distributions. − In this study, the focus is on the development of a hyphenated analytical approach for the study of colloidal material during continuous controlled synthesis (i.e., the microfluidic method).…”

Graphene Oxide of Extra High Oxidation: A Wafer for Loading Guest Molecules

“…The surface was determined by the DFT method and corresponds to (26.6 ± 2.6) m 2 ·g –1 . Usually, the GO surface area according to the literature data is estimated to be 200–600 m 2 ·g –1 , , and the low surface area is due to the association of the layers via hydrogen bonds. Similar results were previously obtained by Ding et al for GO obtained from the waste graphite from diamond synthesis industry.…”