Methacrylate Units Research Articles

Crab and prawn shell utilization as a source of bio-based thermoplastics through graft polymerization with acrylate monomers

To recycle crab and prawn shell wastes and prepare environment friendly thermoplastics, various acrylate monomers—methyl (meth)acrylates, ethyl (meth)acrylates, and butyl (meth)acrylates were grafted onto molecular chains of chitin and crude protein in shells. The acrylates were proved to be successfully grafted onto the demineralized shells through FTIR characterization and grafting parameters of the shell-g-polyacrylates were obtained through titration and Soxhlet extraction. Then, effects of grafting ratio and molecular structure of acrylate monomers on tensile properties and water resistance of the grafted shell thermoplastic films were surveyed. With the increase in grafting ratio of the demineralized shell-g-PMMA, tensile strength of the thermoplastic films initially increased, reached the maximum when the ratio was 31.86%, and then leveled off while both the elongation and water resistance of the film showed an increasing trend. In addition, with the increase in the alkyl chain length of ester group in acrylate unit, tensile strength and water resistance of the grafted shell film decreased continuously while tensile elongation kept increasing. As for α-methyl in methacrylate unit, the film prepared from the shells grafted with methacrylates had higher tensile strength and water resistance but lower elongation than the ones grafted with corresponding acrylates.

PNIPAm-based microgels with a UCST response

Thermoresponsive microgels with an upper critical solution temperature (UCST) response (i.e., showing volume expansion at higher temperature) are highly desirable for a variety of applications, but quite uncommon, in particular if they are to work in physiological conditions. Here we present a novel UCST-type microgel showing a remarkable transition in physiological conditions, with a diameter increase larger than 150% from 34 °C to 40 °C. This novel material is based in poly(N-isopropyl acrylamide), pNIPAm, a polymer well known for its opposite temperature response (featuring a lower critical solution temperature, LCST). The unusual properties of our material are due to a small fraction of copolymerized methacrylic acid and nitrocatechol monomers. The collapsed conformation in PBS buffer below 34 °C is stabilized by hydrogen bonding, with repulsion by partially ionized nitrocatechol and methacrylic units being screened by the ionic strength and the formation of hydrophobic clusters by the methyl groups in methacrylic acid. The increase in temperature leads to the collapse of pNIPAm segments, which disrupts the balance of supramolecular interactions, leading to the large volume expansion of the gel.

Poly(Ethylene Glycol) Dimethacrylates with Cleavable Ketal Sites: Precursors for Cleavable PEG‐Hydrogels

The authors introduce poly(ethylene glycol) (PEG) based macromonomers containing acid-labile ketal moieties as well as terminal methacrylate units that are amenable to radical polymerization. The synthesis of PEGs of different molecular weights (ranging from 2000 to 13 000 g mol-1 with polydispersities <1.15) with a central ketal unit (PEG-ketal-diol) and their conversion to PEG-ketal-dimethacrylates (PEG-ketal-DMA) is introduced. Degradation rates of both PEG-ketal-diols and PEG-ketal-DMA are investigated by in situ 1 H NMR kinetic studies in deuterated phosphate buffer. Hydrogels containing 0, 5, or 10 wt% of PEG-ketal-DMA and 100, 95, or 90 wt% of PEG-DMA, respectively, are synthesized and disintegration of the gels is investigated in buffer at different pH values. Visible disintegration of the gels appears at pH 5 for hydrogels containing PEG-ketal-DMA, whereas no visible degradation is observed at all at neutral pH or for PEG hydrogels without PEG-ketal-DMA.

Single-alkyl and multi-alkyl chain-containing amphiphilic oligomers with several sugar side chains: solution properties and nanostructural analysis of aggregates by SANS

Single-alkyl chain-containing amphiphilic oligomers with a terminal alkyl chain and several sugar side chains (i.e., C n -mGEMA, where n represents alkyl chain lengths of 12 or 16 and m represents the polymerization degree of glycosyloxyethyl methacrylate (GEMA) units of 3.0–7.1), and multi-alkyl chain-containing amphiphilic oligomers with several sugar side chains (i.e., xC12-mGEMA, where x represents the average number of alkyl chains and x–m is 0.2–6.6, 1.8–4.7, and 3.4–3.7), were synthesized via the radical oligomerization of one or two monomers in the presence of alkanethiol or 2-aminoethanethiol hydrochloride. Surface tension, pyrene fluorescence, and small-angle neutron scattering (SANS) measurements were used to characterize the solution properties of the oligomers and the nanostructures of their aggregates. Both amphiphilic oligomers are highly efficient in reducing the surface tension of water (42–48 mN m−1 for C n -mGEMA and 36–46 mN m−1 for xC12-mGEMA), despite the relatively large structures of the hydrophilic parts in sugar GEMA units. The critical micelle concentration (CMC) of C n -mGEMA and xC12-mGEMA increased with an increase in the degree of polymerization for hydrophilic GEMA units and a decrease in the alkyl chain length. The results of SANS determined that C n -mGEMA formed prolate ellipsoid micelles with a radius of 1.96 nm and an axial ratio of 1.58 for a low degree of polymerization (m = 3.0) in solution. However, the radius decreased to 1.33 nm and the axial ratio increased to 5.04 as the degree of polymerization of the amphiphilic oligomers increased to m = 7.1, indicating structural transformation to an asymmetric ellipsoid. On the other hand, the structure of the aggregates formed by xC12-mGEMA changed from ellipsoidal to an ellipsoidal cylinder shape with increasing number of alkyl chains, i.e., decreasing the number of GEMA units.

BAB-random-C Monomer Sequence via Radical Terpolymerization of Limonene (A), Maleimide (B), and Methacrylate (C): Terpene Polymers with Randomly Distributed Periodic Sequences.

A naturally abundant terpene, limonene (A), was radically polymerized with a maleimide derivative (B) and methacrylate (C) in a fluorinated alcohol to give terpolymers with unprecedented BAB-random-C sequences in which the BAB monomer sequence was randomly copolymerized with a C unit. In each binary system, limonene was hardly copolymerized with methacrylate while it was efficiently copolymerized with maleimide to result in a 1:2-alternating BAB periodic sequence, in part due to the penultimate effects and hydrogen-bonding interactions with fluoroalcohol. Methacrylate and maleimide were randomly copolymerized to give copolymers rich in methacrylate units with minimal amounts of maleimide-maleimide sequences. Their terpolymerization resulted in a BAB-r-C sequence as a consequence of the selective BAB polymerization between limonene and maleimide, the random copolymerization between methacrylate and maleimide, and the lack of copolymerization between limonene and methacrylate.

BAB‐random‐C Monomer Sequence via Radical Terpolymerization of Limonene (A), Maleimide (B), and Methacrylate (C): Terpene Polymers with Randomly Distributed Periodic Sequences

AbstractA naturally abundant terpene, limonene (A), was radically polymerized with a maleimide derivative (B) and methacrylate (C) in a fluorinated alcohol to give terpolymers with unprecedented BAB‐random‐C sequences in which the BAB monomer sequence was randomly copolymerized with a C unit. In each binary system, limonene was hardly copolymerized with methacrylate while it was efficiently copolymerized with maleimide to result in a 1:2‐alternating BAB periodic sequence, in part due to the penultimate effects and hydrogen‐bonding interactions with fluoroalcohol. Methacrylate and maleimide were randomly copolymerized to give copolymers rich in methacrylate units with minimal amounts of maleimide–maleimide sequences. Their terpolymerization resulted in a BAB‐r‐C sequence as a consequence of the selective BAB polymerization between limonene and maleimide, the random copolymerization between methacrylate and maleimide, and the lack of copolymerization between limonene and methacrylate.

The effect of the solvent employed in the synthesis of hydrogels of poly (acrylamide-co-methyl methacrylate) on their structure, properties and possible biomedical applications

Polyacrylamide and poly(acrylamide-co-methyl methacrylate) hydrogels were synthesized in three different solvents: water, aqueous dioxane 50vol% and aqueous ethanol 80vol%. The obtained hydrogels were characterized by swelling behavior, FTIR, SEM, optical microscopy (OM) and DSC. The hydrogels showed a significant dependence of their microstructure and other properties with the solvent used during the synthesis. Hydrogels synthesized in water showed a poor incorporation of methyl methacrylate (MMA) units as evidenced by FTIR, while those synthesized in aqueous ethanol 80vol% exhibited a higher incorporation of MMA as compared to the hydrogels obtained in aqueous dioxane 50vol%. Although the incorporation of MMA is higher for the hydrogels synthesized in aqueous ethanol 80vol%, these hydrogels displayed the highest swelling values (e.g., 6500% for the polyacrylamide hydrogel). These values are approximately 7-times higher than the swelling of equivalent hydrogels synthesized in water (900%). DSC results are consistent with swelling behavior, since the difference in the content of free water was 70, 9 and 6mg of free water/mg of xerogel for the hydrogels of acrylamide synthesized in aqueous ethanol 80vol%, water and aqueous dioxane 50vol%, respectively. OM and SEM results reveal highly porous microstructures characteristic of superabsorbent materials. Only hydrogels synthesized in aqueous dioxane 50vol% were studied as potential carriers for ciprofloxacin. Results demonstrated that most of the drug load is released during the first 6h.

PH- and Thermoresponsive Self-Assembly of Cationic Triblock Copolymers with Controlled Dynamics

Transient hydrogels formed by cationic BAB triblock copolymers consisting of a hydrophilic poly(dimethylaminoethyl methacrylate) (P(DMAEMA)) A block and amphiphilic B blocks composed of randomly distributed DMAEMA and n-butyl methacrylate (nBMA) units were investigated. Oscillatory shear measurements revealed formation of dynamic networks with terminal relaxation times that can be controlled by tuning the ionization degree (α) of the DMAEMA units or the temperature up until 50 °C. A sol–gel transition could be induced by increasing the pH. Above 50 °C irreversible aggregation was observed. The behavior of these pH-sensitive cationic copolymers is compared with that of pH-sensitive anionic copolymers, revealing that incorporating stimuli-responsive hydrophilic units within the hydrophobic blocks of amphiphilic block copolymers may be a general way to control the exchange dynamics of the latter.

Multifunctional Polymeric Platform of Magnetic Ferrite Colloidal Superparticles for Luminescence, Imaging, and Hyperthermia Applications.

Adequately designed multiresponsive water-soluble graft copolymers were used to serve as a multifunctional polymeric platform for the encapsulation and transfer in aqueous media of hydrophobic magnetic nanoparticles (MNPs). The backbone of the graft copolymers was composed of hydrophilic sodium methacrylate units, hydrophobic dodecyl methacrylate units, and luminescent quinoline-based units, while either the homopolymer poly(N-isopropylacrylamide) or a poly(N,N-dimethylacrylamide-co-N-isopropylacrylamide) copolymer was used as thermosensitive pendent side chains. The polymeric platform forms micellar-type assemblies in aqueous solution, and exhibits pH-responsive luminescent properties and a lower critical solution temperature behavior in water. Depending on the design of the side chains, the cloud point temperatures were determined at 38 and 42 °C, close or slightly above body temperature (37 °C). Above the critical micelle concentration (CMC), both graft copolymers can effectively stabilize in aqueous media as magnetic colloidal superparticles (MSPs), oleylamine-coated MnFe2O4 MNPs, as well as 1:1 mixture of oleylamine-coated MnFe2O4 and CoFe2O4 MNPs. When CoFe2O4 particles were mixed with MnFeO4 in equal amounts, the specific loss power increased significantly, while an opposite trend was observed in the magnetic resonance imaging (MRI) studies, probably due to the anisotropy of cobalt. As a consequence, fine-tuning of the chemical structure of the copolymers and the composition of the MSPs can lead to materials that are able to act simultaneously as luminescent, hyperthermia, and contrast MRI agents.

Reduced Blood Cell Adhesion on Polypropylene Substrates through a Simple Surface Zwitterionization.

To overcome the thrombogenic reactions of hydrocarbon-based biomaterials in clinical blood treatment, we introduce a model study of surface zwitterionization of a polypropylene (PP) substrate using a set of well-defined copolymers for controlling the adhesion of blood cells in vitro. Random and block copolymers containing zwitterionic units of 2-methacryloyloxyethyl phosphorylcholine (MPC), [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SBAA), or nonionic units of 2-hydroxyethyl methacrylate (HEMA) with a controlled hydrophobic segment of 70% n-butyl methacrylate (BMA) units in these polymers were synthesized through reversible addition-fragmentation chain transfer polymerization. A systematic study of how zwitterionic and nonionic copolymer architectures associated with controlled chain orientation via hydration processes affect blood compatibility is reported. The surface wettability of PP substrates coated with the block copolymer with poly(MPC) (PMPC) segments was higher than that of the random copolymer poly(MPC-random-BMA). However, only the random copolymers with SBAA units demonstrate a higher surface wettability. The PP substrate coated with nonionic copolymers containing HEMA units showed relatively lower hydration capability associated with higher protein adsorption, platelet adhesion, and leukocyte attachment than those with zwitterionic copolymers. The random copolymer poly(SBAA-random-BMA) coated on the PP substrates exhibited resistance to cell adhesion in human whole blood at a level comparable to that of MPC copolymers. An ideal zwitterionic PP substrate could be obtained by coating it with a block copolymer composed of PMPC and poly(BMA) (PBMA) segments, PMPC-block-PBMA. The water contact angle decreased dramatically from approximately 100° on the original PP substrate to 11° within 30 s. The number of blood cells attached on PMPC-block-PBMA decreased significantly to less than 2.5% of that on original PP. These results prove that the rational design of zwitterionic polymers incorporated with a hydrophobic anchoring portion provides a promising approach to reduce blood cell adhesion and protein adsorption of hydrocarbon-based biomaterials applied in direct contact with human whole blood.

Copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride and alkyl methacrylates

Radical copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with methyl methacrylate and allyl methacrylate in the bulk and methanol solution in the presence of azobis-isobutyric acid dinitryle at 70–90°C has been studied. Copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with methyl methacrylate or allyl methacrylate in the bulk proceeds with formation of random copolymers enriched in methacrylate units; in the copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidiny chloride with methyl methacrylate in methanol, the copolymerization constants of the monomers become close. The kinetic parameters of the reaction have been studied, the relative activities of the monomers have been determined. It has been found that 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride is copolymerized with allyl methacrylate or methylmethacrylate to form pyrrolidinium structures in the cyclolinear polymer chain. At high degrees of conversion of the copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with allyl methacrylate, the viscosity increases and the side polymer chains are crosslinked by “allyl bonds” to form insoluble copolymers, swelling in benzene and DMSO.

Alternating Sequence Control for Carboxylic Acid and Hydroxy Pendant Groups by Controlled Radical Cyclopolymerization of a Divinyl Monomer Carrying a Cleavable Spacer

By utilizing features of the hemiacetal ester (HAE) bond: easy formation from vinyl ether and carboxylic acid and easy cleavage into different functional groups (-COOH and -OH), we achieved control of the alternating sequence of two functional pendant groups of a vinyl copolymer. Methacrylate- and acrylate-based vinyl groups were connected through HAE bonds to prepare a cleavable divinyl monomer, which was cyclo-polymerized under optimized conditions in a ruthenium-catalyzed living radical polymerization. Subsequent cleavage of the HAE bonds in the resultant cyclo-pendant led to a copolymer consisting of alternating methacrylic acid and 2-hydroxyethyl acrylate units as analyzed by 13 C NMR spectroscopy. The alternating sequence of -COOH and -OH pendants specifically provided a lower critical solution temperature (LCST) in an ether solvent, which was not observed with the random copolymer of same composition ratio.

Fabrication of diverse pH-sensitive functional mesoporous silica for selective removal or depletion of highly abundant proteins from biological samples

In proteomic studies, poor detection of low abundant proteins is a major problem due to the presence of highly abundant proteins. Therefore, the specific removal or depletion of highly abundant proteins prior to analysis is necessary. In response to this problem, a series of pH-sensitive functional mesoporous silica materials composed of 2–(diethylamino)ethyl methacrylate and methacrylic acid units were designed and synthesized via atom transfer radical polymerization. These functional mesoporous silica materials were characterized and their ability for adsorption and separation of proteins was evaluated. Possessing a pH-sensitive feature, the synthesized functional materials showed selective adsorption of some proteins in aqueous or buffer solutions at certain pH values. The specific removal of a particular protein from a mixed protein solution was subsequently studied. The analytical results confirmed that all the target proteins (bovine serum albumin, ovalbumin, and lysozyme) can be removed by the proposed materials from a five–protein mixture in a single operation. Finally, the practical application of this approach was also evaluated by the selective removal of certain proteins from real biological samples. The results revealed that the maximum removal efficiencies of ovalbumin and lysozyme from egg white sample were obtained as 99% and 92%, respectively, while the maximum removal efficiency of human serum albumin from human serum sample was about 80% by the proposed method. It suggested that this treatment process reduced the complexity of real biological samples and facilitated the identification of hidden proteins in chromatograms.

Copolymeric hexyl acrylate-methacrylic acid microspheres – surface vs. bulk reactive carboxyl groups. Coulometric and colorimetric determination and analytical applications for heterogeneous microtitration

Copolymeric acrylate microspheres were prepared from hexyl acrylate using different amounts of methacrylic acid, resulting in a series of microspheres of gradually changing properties. The distribution of carboxyl groups – between surface and bulk of microspheres was evaluated. Bulk reactive carboxyl groups were determined using reverse coulometric titration with H+ ions, following hydroxide ions have been generated and allowed to react with microspheres in the first step. It was found that the number of reactive carboxyl groups available in copolymeric microspheres is lower compared to number of methacrylic acid units used for polymerization process. Moreover, there is correlation between the number of groups introduced and found to be reactive in microspheres. On the other hand, the number of surface reactive groups was proportional to the number of groups introduced in course of polymerization. Thus, the surface reactive groups can be used as reagent, in novel heterogeneous microtitration procedure, in which a constant number of microspheres of different carboxyl groups contents is introduced to the sample to react with the analyte. The applicability of novel proposed method was tested on the example of Ni2+ determination.

Synthesis of pH-Responsive Multilayer Micelles for Sustained Release of Folic Acid

ABSTRACTTwo novel triblock copolymers poly(hydroxypropyl acrylate)-b-poly (methyl methacrylate)-b-poly(N,N-dimethylaminoethyl methacrylate) and poly(hydroxypropyl acrylate)-b-poly(methyl methacrylate)-b-poly(acrylic acid) were successfully synthesized. In acetone media, using the electrostatic interactions between N,N-dimethylaminoethyl methacrylate and acrylic acid units, they could form spherically shaped multilayer micelles with pH-responsive, and have a mean diameter around 110 nm. The critical micelle concentration of it was determined to be 2.42 mg/L. In vitro release experiments, the folic acid-loaded micelles exhibited sustained release behavior and the drug release rate was affected by the pH value of release media. These results indicate that the multilayer micelles may serve as a novel intelligent drug delivery system.

Preparation and characterization of poly(stearyl methacrylate) grafted natural rubber in latex stage

An attempt to prepare graft copolymer of natural rubber, NR and poly(stearyl methacrylate), PSMA, was made to improve mechanical properties of NR, since the grafted PSMA was composed of crystallizable stearyl groups as a nucleating agent and methacrylate units. The graft-copolymerization of stearyl methacrylate (SMA) onto deproteinized natural rubber (DPNR) was performed in latex stage with tert-butylhydroperoxide (TBHP)/tetraethylenepentamine (TEPA) as an initiator, after purifying the rubber with urea and sodium dodecyl sulphate followed by centrifugation. The optimal conditions for the graft-copolymerization were determined as follows: 3.3 × 10−2 mol/kg-rubber of initiator, 1.5 mol/kg-rubber of monomer and 30 w/w% of dry rubber content (DRC). The conversion and grafting efficiency of SMA were 95 mol% and 60 mol%, respectively. After graft-copolymerization, the melting temperature of PSMA increased from 304.1 K to 306.2 K. The morphology showed that the DPNR particles, which were about 1 μm in average diameter, were well dispersed in PSMA nanomatrix. The stress at break increased about three times, i.e. 13 MPa, as high as that of DPNR. The increase in the mechanical properties was promoted by the nucleating effect of stearyl group of PSMA.

Subconjunctivally Implanted Hydrogels for Sustained Insulin Release to Reduce Retinal Cell Apoptosis in Diabetic Rats.

Diabetic retinopathy (DR) is a leading cause of blindness in diabetic patients that involves early-onset retinal cell loss. Here, we report our recent work using subconjunctivally implantable hydrogels for sustained insulin release to the retina to prevent retinal degeneration. The hydrogels are synthesized by UV photopolymerization of N-isopropylacrylamide and a dextran macromer containing oligolactate-(2-hydroxyetheyl methacrylate) units. Insulin was loaded into the hydrogels during the synthesis. The ex vivo bioactivity of insulin released from the hydrogels was tested on fresh rat retinas using immunoprecipitation and immunoblotting to measure insulin receptor tyrosine and Akt phosphorylation. The biosafety and the effect on the blood glucose of the hydrogels were evaluated in rats 2 months after subconjunctival implantation. The release of insulin from the hydrogels was studied both in vitro in PBS (pH 7.4), and in vivo using confocal microscopy and RIA kit. The in vivo bioactivity of the released insulin was investigated in diabetic rats using DNA fragmentation method. The hydrogels could load insulin with approximately 98% encapsulation efficiency and continuously release FITC-insulin in PBS (pH = 7.4) at 37°C for at least 5 months depending on their composition. Insulin lispro released from the hydrogels was biologically active by increasing insulin receptor tyrosine and Akt serine phosphorylation of ex vivo retinas. In vivo studies showed normal retinal histology 2 months post subconjunctival implantation. Insulin released from subconjunctivally implanted hydrogels could be detected in the retina by using confocal microscopy and RIA kit for 1 week. The implanted hydrogels with insulin lispro did not change the blood glucose level of normal and diabetic rats, but significantly reduced the DNA fragmentation of diabetic retinas for 1 week. The developed hydrogels have great potential to sustain release of insulin to the retina via subconjunctival implantation to minimize DR without the risk of hypoglycemia.

Recovery of Cs(I) by a thermoresponsive metal recovery polymer consisting of an N-isopropylacrylamide unit and a sodium methacrylate unit

Recovery of CsI ions was achieved using a thermoresponsive metal recovery polymer consisting of a sodium methacrylate (SMA) unit for adsorption and an N-isopropylacrylamide (NIPAAm) unit for thermoresponsiveness. The water-soluble polymer efficiently provided homogeneous adsorption at ambient temperature. After adsorption, heating of the resulting solution precipitated CsI-adsorbed polymers that were separable by filtration. The kinetics, pH effect, and effect of the copolymer composition ratio on CsI recovery were investigated. Furthermore, the washing of soil containing CsI ions using an aqueous solution of the polymer was examined. The washed soil was separated by filtration, and heating of the filtrate precipitated CsI-adsorbed polymers that could be recovered by filtration. This indicated the potential utility of thermoresponsive metal recovery polymer in the recovery of the radioactive cesium from contaminated soil.

Self-Assembled Nanoparticle Arrays on Chemical Nanopatterns Prepared Using Block Copolymer Lithography.

We present a high-throughput and inexpensive fabrication approach that uses self-assembled block copolymer (BCP) films as templates to generate dense nanoscale chemical patterns of polymer brushes for the selective immobilization of Au nanoparticles (NPs). A cross-linked random copolymer mat that contains styrene and methyl methacrylate units serves both as a base layer for perpendicular assembly of nanoscale domains of poly(styrene-block-methyl methacrylate) (PS-b-PMMA) films and as a nonadsorbing background layer that surrounds the chemical patterns. The selective removal of the PMMA block and the underlying mat via oxygen plasma etching generates binding sites which are then functionalized with poly(2-vinylpyridine) (P2VP) brushes. Au NPs with a diameter of 13 nm selectively immobilize on the patterned P2VP brushes. An essential aspect in fabricating high quality chemical patterns is the superior behavior of methyl methacrylate containing cross-linked mats in retaining their chemistry during the grafting of P2VP brushes. The use of BCPs with different molecular weights and volume fractions allows for preparation of chemical patterns with different geometries, sizes, and pitches for generating arrays of single particles that hold great promise for applications that range from molecular sensing to optical devices.

“Grafting through” polymerization involving surface‐bound monomers

ABSTRACT“Grafting through” polymerization represents copolymerization of free monomers in solution and polymerizable units bound to a substrate. Free polymer chains are formed initially in solution and can incorporate the surface‐bound monomers, and thereby, get covalently bonded to the surface during the polymerization process. As more growing chains attach to the surface‐bound monomers, an immobilized polymer layer is formed on the surface. We use a combination of computer simulation and experiments to comprehend this process for monomers bound to a flat impenetrable substrate. We concentrate specifically on addressing the effect of spatial density of the surface‐bound monomers on the formation of the surface‐attached polymers. We employ a lattice‐based Monte Carlo model utilizing the bond fluctuation model scheme to provide molecular‐level insight into the grafting process. For experimental validation, we create gradients of density of bound methacrylate units on flat silicon wafers using organosilane chemistry and carry out “grafting through” free radical polymerization initiated in bulk. We report that the proximity of the surface‐bound polymerizable units promotes the “grafting through” process but prevents more free growing chains to “graft through'' the polymerizable units. The “grafting through” process is self‐limiting in nature and does not affect the overall density of the surface‐bound polymer layer, except in case of the highest theoretical packing density of surface‐bound monomers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 263–274