Influence of side chain isomerism on the rigidity of poly(3-alkylthiophenes) in solutions revealed by neutron scattering

Hong, Wonbin; Lam, Christopher N.; Wang, Yangyang; He, Youjun; Sánchez-Díaz, Luis E.; Do, Changwoo; Chen, Wei‐Ren

doi:10.1039/c8cp07520d

Cited by 15 publications

(24 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Before we perform a quantitative analysis of polymer conformation, it is intuitive to investigate the qualitative features of the SANS data by Kratky plots. 45 Kratky plots can qualitatively assess the flexibility of polymers. Figure 3c shows that P3DT-d21 are semiflexible chains as revealed by the high-q upturn in the experimental results that deviate from the predicted plateau of the Debye model for flexible polymer chains.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Thus in this work, we will focus the discussion on P3DT-d21 polymer. Before we perform a quantitative analysis of polymer conformation, it is intuitive to investigate the qualitative features of the SANS data by Kratky plots . Kratky plots can qualitatively assess the flexibility of polymers.…”

Section: Resultsmentioning

confidence: 99%

“…They found that P3ATs are typical semiflexible polymers with persistence length ( L p ) from 1 to 3 nm. Furthermore, Chen et al found that the branched side-chain structure in P3ATs favors chain conformations that involve twisting of the polymer backbone; thus, they are more flexible when compared to P3ATs with linear side chains . Up to now, previous experiments only consider chain conformation as a whole, from which the entire polymer chain shape was determined.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Decoupling Poly(3-alkylthiophenes)’ Backbone and Side-Chain Conformation by Selective Deuteration and Neutron Scattering

Cao

Song

et al. 2020

Macromolecules

Self Cite

View full text Add to dashboard Cite

Although considerable progress has been made to optimize the optoelectronic properties of conjugated polymers (CPs), the rational design of CPs with tailored physical properties for end-use applications remains a significant challenge. Specifically, experimental characterization of conjugated polymer backbone conformations remains underexplored due to limited techniques that are capable of distinguishing the backbone and side-chain structures at nanoscopic resolution. Thus, relating the electronically functional backbone conformation to the material’s macroscopic optoelectronic property is an ongoing challenge. Here, small-angle neutron scattering techniques (SANS) with contrast-variation (CV) experiments are employed on poly(3-alkylthiophenes) (P3ATs) with both deuterated and protonated side chains in a mixture of protonated and deuterated solvents to decouple the backbone and side-chain scattering signals. We obtained the form factor of P3ATs’ backbone, side chains, and cross-scattering term by deconvoluting their respective scattering signals. Poly(3-decylthiophene) shows a persistence length of 1.05 ± 0.1 nm for the conjugated polymer backbone and 2.10 ± 0.2 nm for the entire chain. The strong scattering signal from long and flexible alkyl side chains leads to a seemingly more rigid conjugated polymer, which is further revealed by coarse-grained molecular dynamics (CG-MD) simulations. This work offers a methodology to decouple the scattering contribution from the CPs’ backbone and side chains, thus elucidating the inherent conformation of the electronically active conjugated backbone, which provides guidance for the rational design of next-generation polymeric semiconductors.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Decoupling Poly(3-alkylthiophenes)’ Backbone and Side-Chain Conformation by Selective Deuteration and Neutron Scattering

Cao

Song

et al. 2020

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…(It has been reported that r‐ran P3HT, which is amorphous and more flexible, gives a Δ c p of approximately 0.3 J g −1 K −1 , which is close to the value of PS.) Same argument is applicable to P3(4MP)T, which has a l p of approximately 2–2.5 nm, similar to that of r‐reg P3HT. While for DPP‐based D–A CPs, they tend to have even large l p than r‐reg P3HT due to more rigid backbone .…”

Section: Resultsmentioning

confidence: 89%

Challenge and Solution of Characterizing Glass Transition Temperature for Conjugated Polymers by Differential Scanning Calorimetry

Qian

Galuska

McNutt

et al. 2019

J Polym Sci B Polym Phys

Self Cite

View full text Add to dashboard Cite

Thermomechanical properties of polymers highly depend on their glass transition temperature (T g). Differential scanning calorimetry (DSC) is commonly used to measure T g of polymers. However, many conjugated polymers (CPs), especially donor–acceptor CPs (D–A CPs), do not show a clear glass transition when measured by conventional DSC using simple heat and cool scan. In this work, we discuss the origin of the difficulty for measuring T g in such type of polymers. The changes in specific heat capacity (Δc p) at T g were accurately probed for a series of CPs by DSC. The results showed a significant decrease in Δc p from flexible polymer (0.28 J g−1 K−1 for polystyrene) to rigid CPs (10−3 J g−1 K−1 for a naphthalene diimide‐based D–A CP). When a conjugation breaker unit (flexible unit) is added to the D–A CPs, we observed restoration of the Δc p at T g by a factor of 10, confirming that backbone rigidity reduces the Δc p. Additionally, an increase in the crystalline fraction of the CPs further reduces Δc p. We conclude that the difficulties of determining T g for CPs using DSC are mainly due to rigid backbone and semicrystalline nature. We also demonstrate that physical aging can be used on DSC to help locate and confirm the glass transition for D‐A CPs with weak transition signals. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1635–1644

show abstract

“…As the side-chain structure varies from linear to branching and branch position moves closer to backbone, steric hindrance increases. This then reduces backbone rigidity [63] and planarity, and increase π-π stacking distance, as evidenced by grazing-incidence X-ray diffraction (GIXD) results. We recently reported that π-π stacking distance increases from 3.72 Å for P3HT to 3.88 Å for P3(3MP)T [49].…”

Section: Isothermal Crystallizationmentioning

confidence: 97%

Influence of side‐chain isomerization on the isothermal crystallization kinetics of poly(3‐alkylthiophenes)

Qian

Luo

et al. 2021

Journal of Materials Research

Self Cite

View full text Add to dashboard Cite

Flexible alkyl side chain in conjugate polymers (CPs) improves the solubility and promotes solution processability, in addition, it affects interchain packing and charge mobilities. Despite the well-known charge mobility and morphology correlation for these semi-crystalline polymers, there is a lack of fundamental understanding of the impact of side chain on their crystallization kinetics. In the present work, isothermal crystallization of five poly(3alkylthiophene-2,5-diyl) (P3ATs) with different side-chain structures were systematically investigated. To suppress the extremely fast crystallization and trap the sample into amorphous glass, an advanced fast scanning chip calorimetry technique, which is able to quench the sample with few to tens thousands of K/s, was applied. Results show that the crystallization of P3ATs was greatly inhibited after incorporation of branched side chains, as indicated by a dramatic up to six orders of magnitude decrease in the crystallization rate. The suppressed crystallization of P3ATs were correlated with an increased π-π stacking distance due to unfavorable side-chain steric interaction. This work provides a pathway to use side-chain engineering to control the crystallization behavior for CPs, thus to control device performance.Xiaodan Gu earned his Ph.D. from the Department of Polymer Science and Engineering at the University of Massachusetts Amherst, advised by Prof. Thomas P. Russell, focusing on the self-assembly of block copolymers and their lithographic applications. Subsequently, he started a post-doctoral appointment co-advised by Zhenan Bao and Michael F. Toney at Stanford University and SLAC National Accelerator Laboratory, where he studied the morphology of roll-to-roll printed electronics using real-time X-ray scattering techniques. He moved to the University of Southern Mississippi to start his independent career in 2016. His current research interests revolve around various fundamental polymer physics phenomena related to conjugated polymers and their derivative devices. His group studies structure, dynamic, and morphology of conjugated polymers and aim to link their molecular structures to their macroscopic properties through advanced metrology with an emphasis on scattering techniques. He was awarded ORAU Powe Junior Faculty Enhancement Award in 2019, ACS PMSE Young investigator, and a contributor to "Young Talents" special issue to Macromolecular Rapid Communications, "Emerging investigator" for 2020 Polymer Chemistry, and " Early Career Scholars" for 2021 Journal of Materials Research from MRS.

show abstract

Influence of side chain isomerism on the rigidity of poly(3-alkylthiophenes) in solutions revealed by neutron scattering

Cited by 15 publications

References 44 publications

Decoupling Poly(3-alkylthiophenes)’ Backbone and Side-Chain Conformation by Selective Deuteration and Neutron Scattering

Decoupling Poly(3-alkylthiophenes)’ Backbone and Side-Chain Conformation by Selective Deuteration and Neutron Scattering

Challenge and Solution of Characterizing Glass Transition Temperature for Conjugated Polymers by Differential Scanning Calorimetry

Influence of side‐chain isomerization on the isothermal crystallization kinetics of poly(3‐alkylthiophenes)

Contact Info

Product

Resources

About