Novel excimer fluorescence method for monitoring polymerization: 1. Polymerization of methyl methacrylate

Wang, Francis W.; Lowry, Robert E.; Grant, Warren H.

doi:10.1016/0032-3861(84)90038-7

Cited by 49 publications

(19 citation statements)

References 2 publications

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“…have used 1,3-bis-(1-pyrene) (BPP) to monitor the polymerization of methyl methacrylate in situ. 7 Moorjani and coworkers further demonstrated the utility of fluorescence monitoring when dealing with diffusion-controlled reactions in media of different viscosity. 8 Victor and Torkelson have also used molecular probes to measure the free volume available in polymer structures.9…”

Section: Utility Of Molecular Probesmentioning

confidence: 97%

Characterizing acid mobility in chemically amplified resists via spectroscopic methods

et al. 1999

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State-of-the-art microlithographic processes used to make features smaller than 0.25 microns are based upon deep-UV lithography and chemically amplified resists (CARs). In these resists, photoacid generated during exposure initiates cascading deprotection reactions during post exposure bake (PEB) to form a developable image. Reaction may not be limited to the illuminated areas since the photo-generated protons may diffuse outside this region; therefore, it is important to understand the diffusional characteristics of the photoacid. In this coniribution, the photoacid generation during exposure was characterized using acid-sensitive fluorescence of fluorescein, and the acid mobility and concentration during PEB were studied using crystal violet. These probes were added to the Shipley Apex-E 2408 DUV photoresist, and measurements were carried out in situ on quartz substrates. For fluorescein, characteristic changes in the fluorescence peaks intensities were used to determine the acid concentration during exposure. Crystal violet is a triphenylmethane "propeller" molecule whose excited state lifetime increases as the local free volume decreases, and molecular rotation is hindered. This feature can be used to characterize the free volume in the photoresist using ground state recovery experiments. In addition, crystal violet has three protolytic forms, each with a unique absorption spectrum, and a calibrathxi of the absorption spectrum as a function of acid concentration was used to measure the acid concentration during PEB. These studies illustrate the utility of spectroscopic techniques based upon carefully selected molecular probes to characterize CARs in situ.

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Section: Utility Of Molecular Probesmentioning

confidence: 97%

Characterizing acid mobility in chemically amplified resists via spectroscopic methods

et al. 1999

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“…Since feedback control of the polymer quality is not possible without some form of on-line polymer characterization/monitoring, there have been numerous attempts to achieve it. Such attempts utilize the material's various chemical/physical properties: densitometry (36)(37)(38)(39), refraction and dielectric constants (40), light scattering and turbidity (41), Raman and light scattering (42)(43)(44), and fluorescence (45). Various unresolved problems such as sampling loop clogging, measurement delay, and limited number of monitored variables continue to challenge researchers.…”

Section: Polymerization Monitoringmentioning

confidence: 99%

Monitoring Polymerization Reactions by Near-IR Spectroscopy

Chang

Wang

1995

Multidimensional Spectroscopy of Polymers

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The following overview is an investigative survey on the feasibility of near-infrared (NIR) spectroscopy as an on-line process analytical technique for control and optimization. The review focuses on current developments in the field of polymerization monitoring. A brief background description on instrumentation and methods of data analysis leads to suggestions for further investigation. After NIR's introduction in the early 1950s, it remained unnoticed by polymer chemists and engineers through the 1960s and 1970s. MR recaptured chemical engineers' attention in the late 1980s for two major reasons:(1) the development of advanced optical fiber materials and solid state detectors and (2) the incorporation of recent progress on multivariate data analysis algorithms. A review of the current trends in reactor monitoring strategies comprises the last section.

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“…Polymerization of methyl methacrylate (MMA) was monitored by means of pyrene-labeled alkanes by Wang and coworkers in 1984, [5] measuring the monomer/excimer ratio of pyrene chromophore as a function of time. Neckers described for the first time the linear relationship of pyrene fluorescence ratio with the rate of MMA polymerization at low conversions.…”

Section: Fluorescent Probes For Sensing Processes In Polymersmentioning

confidence: 99%

Fluorescent Probes for Sensing Processes in Polymers

Bosch

Catalina

Corrales

et al. 2005

Chemistry A European J

113

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Fluorescence spectroscopy is an important analytical technique that has been widely used in a variety of applications, such as biomedicine, biology, and science of materials, because it presents some properties which makes it unique, that is, extraordinary sensitivity and selectivity, short delay time (<10(-9) s), and it is neither invasive nor destructive, so it can be used for in situ measurements. Generally, intrinsic fluorescence of many materials, like polymers, is unspecific so it is not useful to analyse their properties or to be correlated to changes in their microenvironment. The incorporation of additives with fluorescent groups would be necessary. When the fluorescence emission of these molecules is sensitive to changes of properties, such as polarity, fluidity, order, molecular mobility, pH, or electric potential, they can be used for detecting such changes in their microenvironment, and they are called fluorescent probes. As long as these probes can follow processes of practical interest, they can be employed as sensors, if the information given by the measure of fluorescence adequately reflects the changes in the system. In addition, a sensor must fulfil some other requirements in order to make them of practical use, the most important being that the material support in which the sensor molecule is inserted. This support should permit a rapid detection of the process and should allow easy processing in a variety of forms. Polymers are well-known systems in which estimation of local parameters are possible by means of fluorimetric techniques. It allows the study of dynamic processes of interest, such as polymerization kinetics and mechanisms, thermal transitions, photodegradation, swelling morphology changes, and so forth.

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Novel excimer fluorescence method for monitoring polymerization: 1. Polymerization of methyl methacrylate

Cited by 49 publications

References 2 publications

Characterizing acid mobility in chemically amplified resists via spectroscopic methods

Characterizing acid mobility in chemically amplified resists via spectroscopic methods

Monitoring Polymerization Reactions by Near-IR Spectroscopy

Fluorescent Probes for Sensing Processes in Polymers

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