Extracting Structural Data from MALDI-ToF Mass Spectrometry Analysis of Alternating Conjugated Polymers - A Case Study on PBTTT Derivatives

Abstract

The incorporation of organic molecules has transformed the (mobile phone) displays market, yet the widespread use of conjugated polymers in optoelectronic applications remains elusive. This can partly be attributed to their inherent dispersity and structural variability. In fact, elucidating the exact molecular structures of state-of-the-art alternating conjugated (co)polymers presents a significant challenge. Matrix-assisted laser desorption/ionization - time-of-flight mass spectrometry (MALDI-ToF MS) is a valuable tool for evaluating polymer structures but its reduced sensitivity for higher molecular weights and nonquantitative nature somewhat restrict its implementation. This study explores MALDI-ToF MS in combination with fractionation to allow detection of longer polymer chains for the benchmark material PBTTT and its alkoxy derivative. Polymers with different homocoupling defect ratios are compared and the information gathered from MALDI-ToF MS is critically assessed. Finally, some guidelines are postulated to assist researchers in extracting pertinent data from MALDI-ToF mass spectra of alternating conjugated polymers.