High Spatial Resolution Imaging with Near-Field Scanning Optical Microscopy in Liquids

• Published in: Analytical chemistry (Washington) 2001-11, Vol.73 (21), p.5015-5019
• Main Authors: Lee, Lynn F, Schaller, Richard D, Haber, Louis H, Saykally, Richard J
• Format: Article
• Language: English
• Subjects: Analysis; Applied sciences; Condensed matter: structure, mechanical and thermal properties; Ethylenes - chemistry; Exact sciences and technology; Fluids; Hexanols - chemistry; Macromolecular and polymer solutions; polymer melts, swelling; Methanol - analogs & derivatives; Methanol - chemistry; Microscopy, Confocal - instrumentation; Microscopy, Confocal - methods; Optics; Organic polymers; Phenol - chemistry; Physicochemistry of polymers; Physics; Polymers - chemistry; Properties and characterization; Sensitivity and Specificity; Solution and gel properties; Solvents; Stress, Mechanical; Structure of solids and liquids; crystallography; Studies of specific liquid structures; Vibration; Vinyl Compounds - chemistry
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac010803k

The mechanism of tuning fork-based shear-force near-field scanning optical microscopy is investigated to determine optimal experimental conditions for imaging soft samples immersed in liquid. High feedback sensitivity and stability are obtained when only the fiber probe, i.e., excluding the tuning fork prongs, is immersed in solution, which also avoids electrical shorting in conductive (i.e., buffer) solutions. Images of MEH-PPV were obtained with comparable spatial resolution in both air and water. High optical resolution (∼160 nm fwhm) was observed.