Pentafluorostyrene Research Articles

One-step Ziegler-Natta polymerization of 4-methylpent-1-ene with pentafluorostyrene – A solution processable copolymer with super hydrophobic properties

Hydrophobic polymers are of high interest in modern membrane applications ranging from blood oxygenation devices to gas diffusion layers in fuel cells. Poly(4-methyl-1-pentene) (PMP) is an interesting membrane material because of its chemical resistance, paired with low density, hydrophobicity, optical transparency, and excellent gas diffusion characteristics. However, the current method of producing PMP membranes through melt processing is not ideal. A more suitable method would be phase inversion via immersion precipitation, but the low solubility of PMP prevents this process. To overcome this processing problem, we propose creating a copolymer of PMP and a fluorinated polymer, which would offer improved solubility and increased hydrophobicity without loss of gas permeability. We successfully synthesize such a copolymer using Ziegler-Natta polymerization of 4-methyl-1-pentene (4 MP) and pentafluorostyrene (PFS). The resulting copolymer exhibits good solubility in a variety of solvents and a critical surface tension γc of 25 mN/m, enabling electrospinning into non-wovens with superhydrophobic properties.

Research in fluorinated block copolymer/polystyrene blends with durable antifouling properties based on chain-entanglement

The durability of antifouling properties is always the problem in fluoropolymer coatings with low surface energy. The bonding between fluorinated polymers of the coating and substrate depends greatly on the penetration with little entanglement in their segments. Segment entanglement is an important factor for the bonding between two polymers, which can be obtained through melt-blending process. In order to create better entanglement and compatibility in fluoropolymers and polystyrene (PS), a kind of block polymers made from pentafluorostyrene (PFS) were prepared by atom transfer radical polymerization (ATRP), with both perfluoroalkyl ethyl group (Fx-group) and alkyl group (Cx-group) on the side. Each side-group played its role respectively through a melt-blending process. At that melting temperature, Fx-group could easily move and aggregate to the surface, and Cx-group would entangle and blend with PS as well. Accordingly, the blends had the surface contact angle of 110.60°(water) and 40.48°(n-dodecane) exhibiting a good antifouling property. Besides, the glass transition temperature (Tg) of the block polymer changed from two peaks to one, after being blended with PS, indicating that block copolymers were completely compatible with PS at the content of 5%wt to 15%wt. It also has been proved by Scanning Electron Microscope (SEM) that the melt-blending process of blends enhanced with more possible entanglement, as the carbon number of Cx-group increased. Therefore, the blends with longer alkyl side-group displayed more durable antifouling properties than coating process, after being polished 160 times by 800-mesh sandpaper or being immersed in ethanol for 96 h. This work will probably provide a new strategy as a substitute of coating process to achieve more durable antifouling properties in general polymer materials.

Removal of anionic and cationic dyes from aqueous solution using thermo- and pH-responsive amphiphilic copolymers

Amphiphilic copolymers exhibiting thermally induced phase segregation in water hold great potential as smart flocculants for water purification. Herein, we report the preparation of thermo- and pH-responsive copolymers based on oligo(ethylene glycol) methacrylate (OEGMA), dimethylaminoethyl acrylate (DMAEA) and pentafluorostyrene (PFS), and their use as thermally induced adsorbents for the removal of anionic and cationic dyes from water. The copolymer self-assembly behaviour in water was first studied as a function of concentration and pH. Then, the potential to remove thiazole yellow G (TYG) and rhodamine B (RhB) was investigated as a function of pH and dye concentration, highlighting that dye removal is mediated by hydrophobic and electrostatic interactions. As regards TYG, at pH 4 a removal capacity (RC) of about 80 mg/g, corresponding to a 97 % dye removal efficiency, was achieved at 800 mg/L TYG. In the case of RhB, a maximum RC value of 32 mg/g was obtained at pH 10. The results reported herein show that these copolymers represent a versatile platform to remove water-soluble organic dyes depending on pollutant concentration and pH conditions.

Constructing interfacial gradient layers and enhancing lithium salt dissolution kinetics for high-rate solid-state batteries

The stability of the interfacial layers depends mainly on the composition and distribution of the decomposition products from solid-state electrolytes (SSEs) in lithium metal batteries. Therefore, the design of SSEs becomes an attractive way to construct a homogeneous stable interfacial layer. Herein, pentafluorostyrene (PFS) as a block is used to generate robust interfacial layers for solid-state batteries. Meanwhile, PFS facilitates the dissociation of lithium salts to produce more free Li-ions which can enhance the ionic conductivity from the results of 7Li solid-state NMR spectra, density functional theory, and molecular dynamics calculations. Subsequently, XPS depth etching and TOF-SIMS characterizations together show that the gradient interfacial layer is composed of a rich C-F bond surface layer and a rich–LiF&Li3N bottom layer, enabling rapid transport and uniform deposition of lithium ions. As a result, the Li/Li symmetric cell can achieve a stable ultra-long cycle time of more than 3000 h at 0.2 mA cm−2 and a critical current density of 2.4 mA cm−2. The as-prepared SSE exhibits a high ionic conductivity of 4.3 × 10−4 S cm−1 at 25 °C and remarkable cycling stability at 0 °C and − 20 °C. Moreover, the lithium metal batteries based on as-prepared SSEs deliver high-rate (2 C) capability and high-voltage (NCM811) stability at room temperatures.

Enhancing high-frequency dielectric and mechanical properties of SiO2/PTFE composites from the interface fluorination

To achieve polytetrafluoroethylene (PTFE)-based composites for high-frequency applications with low dielectric constant, low dielectric loss tangent and low coefficient of thermal expansion (CTE), a novel pentafluorostyrene (PFS) interface modifier was used to achieve excellent performance for SiO2/PTFE composite materials. The effects of PFS modification on the microstructure, dielectric properties and thermal properties of SiO2/PTFE composites were investigated. It is found that the use of PFS greatly improves the interfacial compatibility of the composites, on the one hand the dielectric properties are effectively improved, on the other hand the steric resistance of PTFE matrix is enhanced and the CTE is reduced. When the PFS content of 5 wt%, the CTE of SiO2/PTFE is reduced to 86 ppm/°C. The dielectric loss of the composites varies from 0.71 × 10−3 to 1.53 × 10−3 at frequencies from 5 to 40 GHz. The composites also show stable dielectric properties across the applied temperature (0–150 °C). Benefiting from the high density and uniform microstructure of the PFS-modified composite, enabling it to withstand higher frequency and temperature applications.

Three-layered hollow fiber (HF) membrane and its modification to enhance wetting resistance for membrane distillation (MD)

A three-layered hollow fiber (HF) membrane exhibiting enhanced permeability and wet-resistance was fabricated using polyvinylidene fluoride (PVDF) and poly(vinylidene fluoride–co-chlorotrifluoroethylene) (PVDF–CTFE) simultaneously for membrane distillation (MD). The inner, outer, and middle layers of the membrane were prepared using a macrovoid structure of PVDF–CTFE, the finger-like structure of PVDF, and thin sponge-like structure, respectively. The size of the macrovoid in the inner layer was enlarged and the permeability was enhanced using the polytetrafluoroethylenes (PTFE) as additive. However, the PTFE did not significantly change the liquid entrance pressure (LEP) of the membrane. The LEP and hydrophobicity of the inner layer of HF was increased by grafting pentafluorostyrene (PFS). The prepared membranes were characterized via several analytical tools, and the performance was evaluated using the vacuum MD (VMD) process. With 10% of PTFE, the size of the internal macrovoid increased, thus improving the flux to 137%. When PFS was grafted on the inner layer, the contact angle (CA) and liquid entry pressure (LEP) values increased to 117 and 154%, respectively, that showed an improvement in the wetting resistance. This study showed that the three-layered structure designed using the PTFE and PFS as an additive and grafting, respectively, were successfully fabricated to improve the wetting resistance and permeability.

Well-Defined Thermo-Responsive Copolymers Based on Oligo(Ethylene Glycol) Methacrylate and Pentafluorostyrene for the Removal of Organic Dyes from Water.

Thermo-responsive copolymers based on oligo(ethylene glycol) methacrylate (OEGMA, Mn = 300 g/mol) and pentafluorostyrene (PFS), coded PFG, were synthesized by RAFT polymerization, using a trithiocarbonate (CTTPC) as controlling agent. Different molar masses were targeted and dispersities lower than 1.51 were obtained. The thermally triggered self-assembly of the resulting PFG copolymers in water was investigated by dynamic light scattering (DLS). The lower critical solution temperature (LCST) slightly increased with the molecular weight in the 26–30 °C temperature range, whereas the sizes of the intermicellar aggregates formed upon self-assembly tended to decrease with increasing molecular weights (ranging from 1415 to 572 nm). The resulting thermally-induced polymer aggregates were then used to encapsulate and remove organic contaminants from water. Nile Red (NR) and Thiazole yellow G (TYG) were employed as hydrophobic and hydrophilic model contaminants, respectively. Experimental results evidenced that higher molecular weight copolymers removed up to 90% of NR from aqueous solution, corresponding to about 10 mg of dye per g of copolymer, regardless of NR concentration. The removal of TYG was lower with respect to NR, decreasing from about 40% to around 20% with TYG concentration. Finally, the copolymers were shown to be potentially recycled and reused in the treatment of contaminated water.

Controlled Synthesis of Poly(pentafluorostyrene-ran-methyl methacrylate) Copolymers by Nitroxide Mediated Polymerization and Their Use as Dielectric Layers in Organic Thin-film Transistors.

A library of statistically random pentafluorostyrene (PFS) and methyl methacrylate (MMA) copolymers with narrow molecular weight distributions was produced, using nitroxide mediated polymerization (NMP) to study the effect of polymer composition on the performance of bottom-gate top-contact organic thin-film transistors, when utilized as the dielectric medium. Contact angle measurements confirmed the ability to tune the surface properties of copolymer thin films through variation of its PFS/MMA composition, while impedance spectroscopy determined the effect of this variation on dielectric properties. Bottom-gate, top-contact copper phthalocyanine (CuPc) based organic thin-film transistors were fabricated using the random copolymers as a dielectric layer. We found that increasing the PFS content led to increased field-effect mobility, until a point after which the CuPc no longer adhered to the polymer dielectric.

Scalable preparation of alternating block copolymer particles with inverse bicontinuous mesophases

Block copolymer particles with controlled morphologies are of great significance in nanomaterials and nanotechnology. However, ordered inverse morphologies are difficult to achieve due to complex mechanism and formation conditions. Here we report scalable preparation of amphiphilic alternating block copolymer particles with inverse bicontinuous mesophases via polymerization-induced self-assembly (PISA). Concentrated dispersion copolymerizations (up to 40% solid content) of styrene (St) and pentafluorostyrene (PFS) employing a short poly(N,N-dimethylacrylamide) (PDMA29) stabilizer block lead to the formation of well-defined, highly asymmetric PDMA29-b-P(St-alt-PFS)x block copolymers with precise compositions and various morphologies, from simple spheres to ordered inverse cubosome mesophases. The particle morphology is affected by the molecular weight, solid content, and nature of the cosolvents. The cubosome structure is confirmed by electron microscopies and small angle X-ray scattering spectroscopy. This scalable PISA approach offers facile access to ordered inverse mesophases, significantly expanding the PISA morphology scope and enabling its applicability to the materials science fields.

Fluorinated oligo(ethylene glycol) methacrylate-based copolymers: Tuning of self assembly properties and relationship with rheological behavior

A series of thermo-responsive oligo(ethylene glycol) methacrylate (OEGMA, Mn = 300 g/mol)-pentafluorostyrene (PFS) copolymers was prepared, and the effect of composition on polymer conformation changes and size of the self-assembled particles in solution was studied. Furthermore, the relationship between self-aggregation mechanistic steps in water and rheological properties is reported. Water-soluble OEGMA-PFS copolymers were synthesized at different molar ratios via free radical polymerization, and their phase transition behavior was investigated in detail by dynamic light scattering (DLS), 1H NMR, simultaneous rheometry-FTIR spectroscopy, and transmission electronic microscopy (TEM). All copolymers exhibited sharp and reversible LCST in water. LCST and particle size of the self-assemblying copolymers can be precisely tuned by varying monomer molar ratio. Simultaneous rheometry-FTIR spectroscopy showed that above the LCST, copolymers with higher OEGMA content form micron-sized and hydrated particles, resulting in a pseudo-hydrogel structure. When the hydrophobic character increases, a more significant dehydration of OEGMA side chains leads to a strengthening of polymer chain interactions, resulting in the formation of nanosized and phase-segregated particles. These results are also relevant with a view of using these structures as a template for the preparation of chemically or physically stabilized nanoparticles to be employed for a variety of applications, such as immobilization, controlled release and flocculation in water treatment.

Nitroxide‐mediated polymerization of adamantyl‐functional methacrylates for 193 nm photoresists

Three different methacrylic monomers (γ‐butyrolactone methacrylate (GBLMA), 3‐hydroxyl‐1‐adamantyl methacrylate (HAMA), and 2‐methyl‐2‐adamantyl methacrylate (MAMA)), that are most often terpolymerized for 193 nm photoresists, were studied individually by nitroxide mediated polymerization (NMP) with succinimidyl ester terminated BlocBuilder (NHS‐BlocBuilder) using a small fraction ∼ 0.05 mol/mol (5 mol%) in the initial mixture of 2,3,4,5,6 pentafluorostyrene (PFS) controlling co‐monomer. The copolymerizations were done in 0.35 g/g (35 wt%) dioxane solution and were studied as functions of temperature (75 versus 90 °C) and added free SG1 nitroxide (none versus SG1:NHS‐BlocBuilder molar ratio ≈ 0.15) with the objective of minimizing the dispersity (). MAMA/PFS copolymerizations were not strongly influenced by temperature or addition of free nitroxide, with relatively linear number average molecular weight versus conversion plots and = 1.28–1.55. Further, MAMA/PFS polymerization kinetics was notably slower compared to GBLMA or HAMA copolymerizations with PFS. For GBLMA/PFS and HAMA/PFS copolymerizations, was reduced at the lower temperature of 75 °C but added SG1 did not play a strong role. For GBLMA/PFS, was reduced from 1.70–1.71 at 90 °C to 1.42–1.50 at 75 °C and for HAMA/PFS, was reduced from 1.36–1.47 at 90 °C to 1.22–1.31 at 75 °C.

Wettability adjustment of PVDF surfaces by combining radiation-induced grafting of (2,3,4,5,6)-pentafluorostyrene and subsequent chemoselective “click-type” reaction

A novel strategy combining (2,3,4,5,6)-pentafluorostyrene (PFS) grafting and subsequent thiol/para-fluorine “click” type post-grafting modification is presented to impart specific surface properties to bulky PVDF samples. First, PFS was radiation-induced grafted on the surface of PVDF using γ-rays as the radiation source, and both pre-irradiation and simultaneous irradiation techniques were attempted. The extent of modification was higher with the latter strategy, as determined by semi-quantitative ATR-FTIR analyses. Subsequent coupling was then undertaken using 3-mercapto-1,2-propanediol (MPD). The chemoselective functionalization was qualitatively and semi-quantitatively evidenced by ATR-FTIR, and led to PVDF-g-PPFS decorated with hydroxyl groups. The resulting surface properties were investigated by wettability measurements, and hysteresis with water and contact angle with acetonitrile both evidenced the successful and appropriate modification. This strategy opens the scope of a new means to modify both swelling and surface properties of PVDF samples, as required for specific applications (such as separator in electrochemical devices or in pipe systems for handling specific chemicals).

Tri-Phasic Size- and Janus Balance-Tunable Colloidal Nanoparticles (JNPs).

These studies show synthesis of triphasic size- and Janus balance (JB)-tunable nanoparticles (JNPs) utilizing a two-step emulsion polymerization of pentafluorostyrene (PFS) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) and n-butyl acrylate (nBA) in the presence of poly(methyl methacrylate (MMA)/nBA) nanoparticle seeds. Each JNP consists of three phase-separated copolymers: p(MMA/nBA) core, temperature, and pH-responsive (p(DMAEMA/nBA)) phase capable of reversible size and shape changes, and shape-adoptable (p(PFS/nBA)) phase. Due to built-in second-order lower critical solution temperature (II-LCST) transition of p(DMAEMA/nBA) copolymer, macromolecular segments collapse when temperature increases from 30 to 45 °C, resulting in size and shape changes. The p(DMAEMA/nBA) and p(MMA/nBA) phases within each JNP assume concave, flat, or convex shapes, forcing p(PFS/nBA) phase to adopt convex, planar, or concave interfacial curvatures, respectively. As a result, the JB can be tuned from 3.78 to 0.72. The presence of pH-responsive DMAEMA component also facilitates the size and JB changes due to protonation of the tertiary amine groups of p(DMAEMA/nBA) backbone. Synthesized in this manner, JNPs are capable of stabilizing oil droplets in water at high pH to form Pickering emulsions, which at lower pH values release oil phase. This process is reversible and can be repeated many times.

Synthesis of Narrow Molecular Weight Distribution Norbornene-Lactone Functionalized Polymers by Nitroxide-Mediated Polymerization: Candidates for 193-nm Photoresist Materials

One hundred ninety three-nanometer candidate photoresist materials were synthesized by nitroxide-mediated polymerization (NMP). Statistical copolymerizations of 5-methacryloyloxy-2,6-norboranecarbolactone (NLAM) with 5–10 mol% of controlling co-monomers (which are necessary for controlled polymerizations of methacrylates by NMP with the initiator used) in the feed, such as styrene (ST), p-acetoxystyrene (AcOST), 2-vinyl naphthalene (VN) and pentafluorostyrene (PFS), using the unimolecular BlocBuilder® initiator in 35 wt% dioxane solution at 90 °C were performed. As little as 5 mol% controlling comonomer in the feed was demonstrated to be sufficient to lead to linear evolution of number average molecular weight with respect to conversion up to 50%, and the resulting copolymers had dispersities of ~1.3 in most cases, an attractive feature for reducing line width roughness (LWR) in photoresists. The copolymers generally showed relatively low absorbance at 193 nm, comparable to other 193-nm candidate photoresists reported previously, despite the inclusion of a small amount of the styrenic co-monomers in the copolymer.

The use of effective fragment potentials in the design and synthesis of molecularly imprinted polymers for the group recognition of PCBs

Effective fragment potential (EFP) molecular modeling approaches have been applied for the first time to the rational design of molecularly imprinted polymers for the group recognition of selected polychlorinated biphenyls (PCBs). EFP calculations were benchmarked using the S22 compound test set and returned energies within 1 kcal mol(-1) of the reported gold standard CCSD(T) approach, but without the computational cost. EFP allowed the rapid identification of trimethylstyrene (TMS) and pentafluorostyrene (PFS) as the functional monomers of choice for the templates (T) 1,2,3,4,5-pentachlorobenzene (4) and for 1,2,3-trichlorobenzne (5) respectively. Ethyleneglycol dimethacrylate was the cross linker (CL) of choice. Using a 1 : 2 : 10 (T : FM : CL) ratio for 4 (TMS as the FM; MIP(4-TMS)) gave imprinting factors (IF) of 2.1; and a 15 : 6 : 29 ratio for 5 gave an IF of 3.66 (PFS as FM; MIP(5-PFS)). MIP(4-TMS) and MIP(5-PFS) showed low levels recognition for non-chlorinated templates with IF values ranging of 1.05, 1.17 and 1.13, 1.54 for toluene (14) and 2,6-dimethylaniline (12) respectively. Higher levels of recognition were observed for the chlorinated analogues 1,3,5-trichlorobenzene (11) and 2,4,6-trichloroaniline (12) with IF values of 1.20, 1.64 and 1.89, 2.66 for MIP(4-TMS) and MIP(5-PFS) respectively suggesting these MIPs were suitable for fragment imprinting of PCBs. Fragment imprinting of 2,2',3,5'-tetrachlorobiphenyl (15), 2,3,3',4,4'-pentachlorobiphenyl (16) and 2,2',3,3',4,5,6'-heptachlorobiphenyl (17) with MIP(4-TMS) gave IF values of 1.38, 1.38 and 1.41 respectively. MIP(5-PFS) performed significantly better with IF values of 6.57, 3.46 and 5.80 for 15-17 respectively. Moreover MIP(5-PFS) displayed a higher binding capacity than MIP(4-TMS) and was less susceptible to non-specific binding influences.

Probing the effects of π-π stacking on the controlled radical polymerization of styrene and fluorinated styrene

The addition of the π–π stacking agent octafluorotoluene (OFT) resulted in up to a 50% reduction in monomer conversion after 24 h for atom transfer radical polymerization (ATRP) reactions of styrene, when performed at 85 °C with 1 eq of OFT compared with styrene in the initial reaction mixture. Monitoring the progress showed that the ATRP of styrene in the presence of either OFT or hexafluorobenzene (HFB) maintained a linear relationship between monomer conversion and number average molecular weights, while showing a first order rate dependence on monomer. The effects of π–π stacking on the KATRP could be overcome by using adjusting the redox activity of the metal-ligand complex while maintaining reaction temperatures of 85 °C. Further experiments showed that nitroxide-mediated polymerizations of St were affected to an identical extent by the presence of the π–π stacking agent HFB. The ATRP of pentafluorostyrene (PFSt) in the presence of π–π stackers benzene or toluene showed an increase in monomer conversion compared with reactions in their absence, consistent with Mn π–π stacking increasing the stability of the active radical. Interactions between the π–π stacking agents OFT and HFB and the aromatic groups in the ATRP of St or PFSt were verified by 1H NMR analysis. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Adhesion of Preosteoblasts and Fibroblasts onto Poly(pentafluorostyrene)‐Based Glycopolymeric Films and their Biocompatibility

An efficient and metal-catalyst free method of glycopolymer synthesis via thiol/para-fluorine "click" reaction was used to graft acetylated 1-thio-β-D-glucopyranose and 1-thio-β-D-galactopyranose onto a homopolymer of pentafluorostyrene (PFS) as well as onto a block copolymer of styrene and PFS. Subsequent deprotection of the carbohydrate moieties yielded well-defined, sugar-modified polymers (PDI < 1.2). The prepared polymers were not cytotoxic against 3T3 fibroblasts and MC3T3-E1 preosteoblasts. Furthermore, the water-insoluble copolymers were drop-cast and examined as synthetic biocompatible coatings on poly(propylene) substrates for culturing the investigated cell types. Both fibro- and preosteoblasts showed stable adhesion and proliferation on the glycopolymer-coated surfaces.

Synthesis and characterization of trifluoromethyl substituted styrene polymers and copolymers with methacrylates: Effects of trifluoromethyl substituent on styrene

2-Trifluoromethyl styrene (2TFMS), 2,5-bis(trifluoromethyl) styrene (25BTFMS), and 3,5-bis(trifluoromethyl) styrene (35BTFMS) were synthesized. These styrenes were readily polymerized in bulk and also in solution using AIBN as a free radical initiator. The polymerization rate of these trifluoromethyl substituted styrenes and other monomers such as styrene (St), pentafluorostyrene (PFS) and 4-trifluoromethyl-tetrafluorostyrene (TFMTFS) were measured in benzene and dioxane by monitoring the 1H NMR spectra of the double bond hydrogen. The order of polymerization rates was TFMTFS > 35BTFMS > 25BTFMS > PFS > 2TFMS > St. Tgs of styrene polymers with CF3 substituted on the ortho position of the phenyl ring were much higher than those of the meta and para substituted styrenes due to the steric hindrance of the bulky CF3 group close to the polymer main chain, which resulted in a decrease in the segment mobility of the polymer chains and an increasing Tg of the polymers. The copolymers of 2TFMS with methyl methacrylate (MMA) and also 25BTFMS with trifluoroethyl methacrylate (TFEMA) were prepared. Tgs of the copolymers were in the range of 120–145 °C and the copolymers were transparent and thermally stable. The copolymer films were flexible and exhibited high transmittance as the homopolymers of MMA and TFEMA. Thus, these copolymers may be utilized as novel optical materials.

Synthesis, post-modification and self-assembled thin films of pentafluorostyrene containing block copolymers

Block copolymers consisting of a pentafluorostyrene (PFS) block and a hydrophilic block were synthesized by RAFT polymerisation. The hydrophilic blocks consist of methacrylate derivatives, 4-hydroxystyrene or 4-vinylpyridine monomers. The block copolymers were obtained with narrow molecular weight distributions and the molecular weights were in good agreement with the theoretical values. In addition, a model thiol was reacted with the PFS moieties of the block copolymers. This polymer–analogous reaction was performed under ambient conditions in high yields resulting quantitatively in para-substitution of the pentafluorophenyl rings. Finally, thin films consisting of block copolymers that showed strong phase-segregation behaviour and ordered nanostructured surfaces consisting of both blocks were obtained.

Synthesis and properties of copolymers of methyl methacrylate with 2,3,4,5,6-pentafluoro and 4-trifluoromethyl 2,3,5,6-tetrafluoro styrenes: An intrachain interaction between methyl ester and fluoro aromatic moieties

2,3,4,5,6-Pentafluoro and 4-trifluoromethyl 2,3,5,6-tetrafluoro styrenes were readily copolymerized with methyl methacrylate (MMA) by a free radical initiator. The copolymers were soluble in tetrahydrofuran and acetone. The films obtained were transparent and flexible. The glass transition temperatures (T g S) of the copolymers were found positively deviated from the Gordon-Taylor equation. The positive deviation could be accounted for by dipole-dipole intrachain interaction between the methyl ester group of MMA and the highly fluorinated aromatic moiety, which resulted in a decrease in the segmental mobility of the polymer chains and the enhanced T g values of the copolymers. The water absorption of PMMA was greatly decreased by copolymerization of MMA with the highly fluorinated styrenes. With as little as 10 mol % of pentafluoro styrene content in the copolymer, the water absorption was decreased to one-third of that for pure PMMA. The fluorinated styrenes-MMA copolymers were thermally stable up to 420 °C under air and nitrogen atmospheres. With 50 mol % of MMA in the copolymer, the copolymer was still stable up to 350 °C. Since these copolymers contain a large number of fluorine atoms, the light absorption in the region of the visible to near infrared is decreased in comparison with non-fluorinated polymers. Thus, these copolymers may be suitable for application in optical devices, such as optical fibers and waveguides.