Method for characterizing melting transition and crystallization in a semicrystalline polymer

Inventors

Jin, Kailong • Nile, Richard

Abstract

A method for characterizing a melting transition in a semicrystalline polymer is disclosed. The method includes incorporating a fluorophore into the semicrystalline polymer, changing a temperature of the semicrystalline polymer to vary across a range of temperatures including a plurality of temperatures, and capturing an emission spectrum of the incorporated fluorophore at each temperature of the plurality of temperatures. The method also includes integrating each emission spectrum to determine a temperature-dependent integrated fluorescence intensity for the semicrystalline polymer, numerically differentiating the temperature-dependent integrated fluorescence intensity, and characterizing the melting transition of the semicrystalline polymer by identifying a stepwise change in value of the differentiated intensity. The semicrystalline polymer may be a thermoplastic. Incorporating the fluorophore into the semicrystalline polymer may include physically doping the semicrystalline polymer with the fluorophore or covalently labeling the semicrystalline polymer with the fluorophore.

Core Innovation

The invention provides a fluorescence-based method for characterizing a melting transition in a semicrystalline polymer by incorporating a fluorophore into the semicrystalline polymer and changing a temperature of the semicrystalline polymer to vary across a range of temperatures comprising a plurality of temperatures. At each temperature of the plurality of temperatures, an emission spectrum of the incorporated fluorophore is captured from the semicrystalline polymer.

For each captured emission spectrum, the method integrates the emission spectrum to determine a temperature-dependent integrated fluorescence intensity for the semicrystalline polymer. The temperature-dependent integrated fluorescence intensity is then numerically differentiated to obtain a differentiated intensity.

The melting transition is characterized by identifying a stepwise change in value of the differentiated intensity. In embodiments, the melting transition includes melt crystallization and is observed over a temperature range from 195°C to 60°C.

The disclosure further describes embodiments in which the fluorophore is incorporated by physical doping or by covalent labeling, and examples of fluorophore species including 1,2-bis(2,4-dihydrobenzylidene) hydrazine, TPE (1,1,2,2-tetraphenylethene), and pyrene are incorporated into semicrystalline polymers. The disclosure also describes sample handling in which the semicrystalline polymer with incorporated fluorophore is cast on a quartz slide from a solution comprising the semicrystalline polymer with incorporated fluorophore.

Claims Coverage

Two independent claims cover fluorescence-based, temperature-resolved characterization of melting transitions in semicrystalline polymers using a fluorophore signal, integrating emission spectra, numerically differentiating integrated fluorescence intensity, and detecting the transition through a stepwise change in the differentiated intensity. Across the claim sets, at least four inventive features are repeatedly specified: fluorophore incorporation, temperature sweeping with emission capture, integrated fluorescence intensity determination with numerical differentiation, and stepwise change detection; dependent claim sets further narrow transition type, observation temperature range, fluorophore incorporation mode, fluorophore identity, and sample handling on a quartz slide.

Claim coverage centers on identifying melting transitions in a semicrystalline polymer by incorporating a fluorophore, capturing temperature-dependent emission spectra, integrating each spectrum to obtain a temperature-dependent integrated fluorescence intensity, numerically differentiating that intensity, and characterizing the melting transition by identifying a stepwise change in the differentiated intensity. Dependent claims further specify melt crystallization, an observation temperature range of 195°C to 60°C, physical doping or covalent labeling for fluorophore incorporation, specific fluorophore species, and casting the fluorophore-incorporated polymer on a quartz slide from a solution.

Stated Advantages

Documented Applications