Impacts of integrated marketing communications on customers’ green brand awareness: an empirical case study in Vietnam

Vietnam is a country with a dynamic economy, but is facing environmental problems. In the context of economic integration, greening production and consumption is becoming more and more popular in the country. This study focused on examining the impacts of integrated marketing communications on customers’ green brand awareness in Vietnam. We applied Attitude-Behavior-Context theory to build conceptual model and hypotheses. The study collected primary data from 615 customers in Hanoi using the convenience sampling method. Descriptive statistical analysis, Anova test, Cronbach’s Alpha analysis, exploring factor analysis and multivariate regression were used for data analysis. The results showed that there were 6 factors significantly impact green brand awareness including advertising, direct marketing, internet marketing, sales promotion, public relations and personal selling of which advertising was the strongest driver. This research provided brand managers and marketers with clear insight into the mechanisms for improving environmental awareness. It also suggested that companies should design their advertising to highlight the brand’s environmental responsibility and the eco-friendly attributes of products to raise environmental awareness among consumers.


Introduction
Nowadays, industrial processes are causing serious environmental pollution worldwide and have therefore attracted society's attention (Hartmann and Apaolaza-Ibáñez 2012, He and Chen 2016, Chen et al 2020).Facing with market demands and social pressures, businesses have been developing green processes/products for building their image towards greening (Ailawadi and Keller 2014, Huang et al 2014, Cooper and Schindler 2023).Several industries have taken action and necessary steps to reduce pollution and carry out social responsibility regarding the environment.These measures include green marketing or the practice of promoting products that are sustainable and eco-friendly.Industries that invest in green marketing benefit from increased customer loyalty and a positive brand reputation, while also helping protect the planet and contributing to a more sustainable future (Ailawadi andKeller 2014 Hutchins andRodriguez 2018).In other words, due to growing public awareness, it is important to require product companies to ensure that their products are safe for consumers, environmentally friendly and harmless.In this case, consumers demand that marketers be more careful when making decisions that affect the environment (Kang andHustvedt 2014, Godey et al 2020).Yet, companies use green marketing strategies as a competitive advantage.There are some key reasons for companies to practice green marketing which include improving corporate image, increasing product value, enhancing brand value, boosting advantage, and following environmental norms (Demo and Neiva 2012, Chen and Peng 2018, Chen et al 2020).
In reality, promotion of green brand awareness (GBA) is a key solution to communicate with stakeholders in the harsh environment since it promotes customer understanding about green dimensions of the products, builds trust and imprints the brand and product image in the customer's mind (Schmitt 2012, Bekk and Kerschreiter 2016, Grubor and Milovanov 2021).However, changes in marketing have gone beyond the usual traditional marketing frameworks leading to demand brands in the industry especially domestic brands also having to have new concepts to be able to create a deeper connection between brands and customers.Because of changes and brand competition in that industry, brands are under pressure to improve customer perception of their brand to compete with larger international brands (Schmitt 2012, Kapitan andKennedy 2019).It also comes from the pressure from insight and expectations of potential customers as they increasingly value their experiences and first impressions through the senses and perceived value instead of only caring about quality, requiring brands to focus on reaching in depth instead of breadth (Indumathi 2018, Kordos andVojtovic 2022).In addition, digital incentives with increasingly interactive activities on the internet promote reaching broader customer groups, helping to effectively improve brand awareness (Kumar et al 2020).Therefore, the search for planned marketing methods is motivated as it creates a combination of offline and online that is more relevant than ever when a comprehensive approach is possible.These are methods with strict, specific steps to create communication products that are cohesive and effectively increase brand awareness, which is increasingly being paid attention to and used in marketing to increase customer awareness of the green brand (Lawal et al 2017, Ghasemi and Valmohammadi 2018, Chu and Chen 2019).
In Vietnam, it is implied that major innovations in the field of marketing and communication have exploded in recent years as a representative for adaptation in the face of constant market movements including green products (Duc et al 2022).Specifically, these products are characterized by high competition between domestic and foreign businesses, making efforts to build GBA become enormous (Le and Nguyen 2019).According to Le and Truong (2019), about 80% of Vietnamese consumers are willing to pay premium for products with environmentally friendly materials.Hence, it is an advantage for businesses when building a sustainable development brand for themselves, focusing on innovation, integration, joining hands to protect the environment and being supported by a large number of consumers (Truong 2021, Mai et al 2023).
The above pressures related to competitors, customers and digitalization drive the search for solutions as it plays a huge role in the green product market in Vietnam (Le and Truong 2019, Le and Nguyen 2019, Mai et al 2023).As a solution, integrated marketing communication (IMC) plan is applied by marketing researchers such as (Esch and Langner 2016) and businesses in these industries when different approaches to reaching consumers, including digital, social, experiential and traditional advertising approaches, are applied in harmony.It is considered a smart method to comprehensively approach marketing aspects to reach GBA.More specifically, some companies aims to go beyond simply increasing brand recognition; it seeks to cultivate a meaningful and lasting connection between products and its desired audience in Vietnam (Duc et al 2022).This strategy finds its basis in research affirming that a comprehensive marketing approach can empower customers to gain a profound insight into a brand, thereby fostering accelerated engagement with the brand's offerings.It is crucial to emphasize that Vietnamese consumers, much like those in various other nations, exhibit distinct preferences and behaviors, necessitating the adoption of a diverse range of marketing strategies to effectively captivate their interests (Chen andChang 2012, Fraj andMartínez 2013).
Recent studies around the world have so far identified many factors affecting GBA.The majority of studies showed that there is a significant relationship between attitudes, awareness and environmental norms with GBA (Eneizan et al 2016, Ghasemi and Valmohammadi 2018, Chen et al 2020, Godey et al 2020).Research has also used many theoretical models to explain and analyze influencing factors, the most popular of which are the Theory of Planned Behavior (TPB), Technology Acceptance Model (TAM) and Attitude-Behavior-Context Theory (ABC).However, there is currently a lack of research on GBA applying these theories in the context of transition economies like Vietnam (Le and Nguyen 2019).Rapid economic growth with diverse impacts on social trends has changed Vietnamese customers' brand awareness and behavior.Along with that, specific cultural and political characteristics can also create unique characteristics of brand identity, including green brands.Vietnam is also a country with a young population with 80% of the population in working age and young people are supplemented with new life values following the world's integration trend.The above arguments show the gaps in theory and practice and the need to explore drivers of GBA in Vietnam to contribute to the literature on this topic.
This study fills in the above gap with aims to examining the impacts of IMC on customers' GBA in Vietnam.The study has both theoretical and practical significance.Regarding theory, the research supports the expansion of academic knowledge surrounding the concepts of IMC and brand awareness and their relationship in the specific context of green products in the Vietnamese market.From there, it contributes to GBA theoretical framework, which can be functional and applied to other research in transition economies.As for practical contributions, this research offers precise recommendations and tactics to raise GBA in the Vietnam for stakeholder.The findings and suggestions from this study will aid businesses in better understanding how to enhance their marketing approach, make better use of their resources, and have more satisfying interactions with their customers and this might increase green products sales and their market share in the market.
The article is structured as follows: the Introduction section introduces the context, rationale and contributions of the research, section 2 describes the theoretical framework and develops hypotheses in the research model, section 3 -methodology includes data collection and data analysis model, section 4 presents main research results, finally section 5 discusses research results and proposes management implications.

Theoretical framework and model development
2.1.Theoretical framework 2.1.1.Green brand awareness Marketing experts have given different views on the definition of brand awareness.Brand awareness, as defined by Garg (2015) is the ability of individuals to recognize or recollect a specific product or service.This concept is rooted in Aaker's theory, which asserts that brand awareness pertains to a potential customer's capacity to retain or retrieve an organization's identity, allowing for the development of a positive association with that brand.Expanding upon Aaker's framework, Ferraro et al (2013) argued that brand consciousness is an essential factor in how customers make decisions and is a critical aspect of comprehending a brand, a view aligned with (Chen and Chang 2015) perspective.In particular, brand awareness is divided into 4 different levels based on Aaker's model.The lowest level of customer's awareness signifies a lack of awareness about the brand.This is followed by brand recognition, often featured as aided recall since it involves recognition with some form of assistance.Next is unaided brand recall, where consumers can remember the brand without external reminders, often referred to as top-of-mind awareness.The pinnacle of brand awareness is the state where a brand is spontaneously recalled by consumers, representing the highest level of brand recognition in consumers' perceptions, as identified by various researchers (Dwivedi 2014, Chen andChang 2015).
According to Garg (2015), a green brand is a set of attributes and benefits associated with reducing impact on the environment and are considered environmentally friendly.In other words, green branding refers to the perception in the consumer's mind about the green dimensions of product or service.In the context of environmentally friendly products, GBA can be defined as the ability of consumers to know and remember that the brand has environmentally friendly products.In principle, GBA explains the ability of consumers to recognize and take into account that these brands have environmentally friendly characteristics.Common measures taken in GBA recognition include environmentally friendly product brand recognition, environmentally friendly product brand recognition, quick recall of eco-friendly product brands environment, quickly recognize environmentally friendly product brands and easy to find, environmentally friendly product brands (Aguirre and Bosnjak 2012, Harandi and Bokharaeinia 2018, Xie and Zheng 2019).

Integrated marketing communication (IMC)
Before substantial shifts occurred in the marketing paradigm, the concept of IMC was considered a novel approach.Ailawadi and Keller (2014) offered a definition of IMC as the systematic amalgamation of promotional tools, marketing communication tactics, and internal resources within an enterprise.This integration is aimed at constructing a cohesive program that exerts the most profound impact on both clients and end-users, all while maintaining cost-effectiveness.Dwivedi and Johnson (2015) provided a similar perspective, describing IMC as the harmonization of communication channels to deliver succinct and uniform messages pertaining to an organization's identity and its offerings.It is a method of planning marketing activities to optimize the depth and breadth of reaching customers systematically in both offline and online marketing when combining tools consistently that creates a seamless customer experience (Lin et al 2017).In particular, IMC uses six typical tools called promotional mix including advertising, direct marketing, internet marketing, sales promotion, public relations and personal selling (Goh andBalaji 2016, Xie andZheng 2019).

The attitude-behavior-context theory
Incorporating attitudes into the model, the Attitude-Behavior-Context (ABC) theory, recognized as one of the most widely cited frameworks for elucidating relationships involving attitudes (Aguirre and Bosnjak 2012), remains pertinent in the context of this study, particularly when considering brand awareness within the domain of attitudes.This theoretical construct, originally developed by, serves to delineate the intricate interplay among 'context', 'attitude', and 'behavior'.More specifically, it posits that the contextual setting exerts an influence on attitudes, subsequently influencing behavioral responses.Notably, the contextual environment directly impacts attitudes.In the context of this study, the concept of IMC assumes the role of a contextual factor, influencing the formation of attitudes and subsequent behaviors by establishing the framework through which marketing messages traverse diverse communication channels (Xie and Zheng 2019).In parallel, brand awareness resides within the realm of attitudes, encapsulating individuals' perceptions and recognition of specific brands (Dwivedi and Johnson 2015) given these attributes; this model can effectively illustrate the relationship between IMC and the overarching construct of brand awareness within the broader theoretical framework.

Hypothesis development 2.2.1. Impact of advertising on GBA
According to Grubor and Milovanov (2021), advertising is 'any paid form of non-personal presentation and promotion of ideas, goods or services by an identifiable sponsor'.Indumathi (2018) found a two-way causal relationship between advertising and sales.Advertising is believed to influence consumer thinking and taste, which ultimately contributes to consumer purchasing behavior.Advertising uses several types of media, each with its own benefits and limitations.Major media types include: (1) television, (2) digital, mobile and social  media, (3) newspapers, (4) direct mail, (5) magazines, (6) radio and (7) outdoor (Eneizan et al 2016).Although it is one of the largest expense items on the income statement, companies of many different industries and sizes use advertising to drive sales and improve their market image.
Among the factors affecting GBA, advertising is considered one of the factors with the strongest impact.Advertisement is considered effectively to influence brand awareness since it may attack the rational and emotional aspects of prejudice in the eyes of customers through many different channels.Grimmer and Bingham (2013) showed that the influence of advertising was the greatest driver of GBA in a study case of Indonesia.Some other researchers also indicated similar results for several industries which utilized creative advertising campaigns to create a distinct impression for their green brands (Joshi andRahman 2015, Lin et al 2017).Advertising aims for creating long-term associations with customers to gain their loyalty and recognition, thereby increasing the company's profits.A common point in previous studies is that green brand acts as an important tool that improves the competitiveness of businesses in different countries where customers are faced with millions of choices (Brown andZablah 2011, Goh andBalaji 2016).This has led companies to direct more resources towards green marketing activities , but it has also required them to seek investments and forms of advertising.As to Joshi and Rahman (2015), creating GBA through advertising has been proposed as a management philosophy to transform the commercial actions of companies to increase financial results.
H1: Advertising has a positive impact on customers' GBA.

Impact of direct marketing on GBA
Previous studies have often suggested that direct marketing is an aspect of online and offline communications that can assist in building customer GBA (Chen and Chang 2012, Rambocas and Ramsubhag 2018).In particular, the coffee industry is an attractive and typical context to explore this relationship.The observed positive correlation can be elucidated by the researchers' explanation, which posits that these tactics facilitate direct engagement between brands and consumers (Joshi and Rahman 2015).Through channels such as email, text messages, postal mail, and various social media platforms, companies can forge personalized interactions finely tuned to their specific target demographics.For instance, coffee industry leaders like Dunkin' and Nescafé have initiated email marketing campaigns aimed at promoting novel products, disseminating brewing recommendations, and furnishing exclusive discounts exclusively to their subscribers (Dwivedi 2014).This deliberate and focused outreach to their customer base significantly bolsters their presence within the customer's sphere of awareness.Consequently, these concerted endeavors culminate in heightened brand visibility and enhanced brand recognition.H2: Direct marketing has a positive impact on customers'GBA 2.2.3.Impact of internet marketing on GBA Internet marketing, also known by other names such as web marketing, online marketing or e-marketing, is a form of marketing through the Internet environment such as electronic mail (email) or social networking sites, online websites and wireless devices.When using Internet marketing, businesses will easily convey product messages, reach potential customers and positively impact consumer psychology.Besides, Internet marketing also helps businesses create lasting relationships with their customers.Previous studies showed that internet marketing has become an explosive communication tool that helps create meaningful connections to create GBA for customers.It revolves around the creation of visually captivating content, interactive social media posts, and direct engagement with customers, all of which play a pivotal role in establishing a robust online presence across various social media platforms (Chong et al 2011, Baumgarth 2014).Additionally, Kinoti (2011) showed that harnessing the potential of search engine optimization (SEO) contributes significantly to enhancing brand visibility and virial content, specifically in developing nations.These strategies have empowered brands to establish direct connections with consumers, bolster their digital footprint, and elevate brand recognition (Kinoti 2011).This is primarily attributed to intrusive advertising practices, the proliferation of misleading information, and concerns surrounding data privacy, all of which can tarnish a brand's reputation and erode its digital presence.Ineffectively oriented content may also contribute to misaligned customer perceptions of the brand.With GBA, internet marketing helps customers easily look up information related to businesses' products and their green behavior through detailed images and overview videos posted by the company.H3: Internet marketing has a positive impact on customers' GBA.

Impact of sales promotion on GBA
Promotion is a sales support marketing activity whose nature is to temporarily increase product value to stimulate short-term consumption (Grubor and Milovanov 2021).According to Joshi and Rahman (2015), promotion is one of the key tools of the promotion mix.There are two main types of promotions: promotions aimed at consumers and promotions aimed at organizational customers.Consumer-directed promotions are understood as stimuli that impact consumers to motivate them to try, repeat, or buy more through a number of tools such as coupons, discounts, gifts, organizing contests, lucky draws, trial samples, loyalty programs, accumulated points (Kang and Hur 2012).Promotions also have an impact on customers' brand awareness (Indumathi 2018, Chen et al 2020).Chen et al (2020) examined the impact of different promotional tools on brand awareness in China.Research showed that a positive corporate image can be created by using various promotional tools, such as discounts, samples and buy one get one free.In a study on the influence of promotions on consumer perception in Malaysia, showed that the product image that customers perceive can be influenced by 5 promotional tools including Coupons, discounts when purchasing additional products of the same type, samples, free gifts, and discounts on products.In a similar study on the impact of promotions on consumer brand awareness in India, Kang and Hur (2012) showed that discounts and product trials have a significant impact on brand awareness and brand loyalty (Papista and Dimitriadis 2019).This strategy is also found in companies such as Starbucks to enhance their brand visibility and recognition, which is proven in the US market (Joshi and Rahman 2015).H4: Sales promotion has a positive impact on customers' GBA 2.2.5.Impact of public relations on GBA Image is an important aspect of brand identity, influencing whether your potential customers know, like and trust you.Because the public is out of control, public relations (PR) is an effective way to contribute to the connection between brands and the public (Fraj and Martínez 2013, Chen and Peng 2018, Hutchins and Rodriguez 2018).PR often focuses on maintaining the image of a company, individual or brand.They create media, public opinion and ensure customers have a positive attitude towards the company's brand.Previous studies have demonstrated the impact of PR on GBA for several businesses (Chen and Peng 2018, Papista and Dimitriadis 2019).Several multinational companies have made use of PR to build a desirable brand image including GBA (Kang andHur 2012, Lipiäinen andKarjaluoto 2015).In the context of increasing environmental and social challenges, building a responsible and sustainable brand image is more important than ever for businesses.Implementing environmental protection initiatives will help businesses impress their customers, thereby influencing their decisions to purchase and use services.In general, green PR is not only a temporary trend but also a sustainable and important direction in the future.Businesses that effectively deploy green PR not only increase brand awareness, but also contribute to environmental protection and create their own long-term economic benefits (Hutchins and Rodriguez 2018).H5: Public relations have a positive impact on customers' GBA.
2.2.6.Impact of personal selling on GBA In the fiercely competitive marketplace, personal selling is one of the marketing strategies frequently used to increase brand recognition (Park and MacInnis 2010).In fact, buying and selling is a complex communication process between sellers and buyers based on understanding of social psychology.Therefore, sales are considered a personalized process to increase interaction between sales staff and potential customers, having a direct impact on customers' buying decisions.With the development of With the Internet and the explosion of social networks, Personal Selling is not limited to face-to-face meetings anymore, but now, sales staff will perform many other tasks and reach customers at many touch points such as phone calls, emails and messages, Instagram to develop relationships with potential customers (Chu and Chen 2019).Previous studies provide a consistent view that personal selling has a positive influence on brand identity (Chen and Chang 2012, Rambocas and Ramsubhag 2018).Direct communication between sellers and potential customers has made it possible for both parties to thoroughly discuss and exhibit the qualities, advantages, and values of the brand (Lipiäinen and Karjaluoto 2015).Then, when it is highly individualized, it generates sensations that are more genuine and trusted than bulk advertising.Additionally, effective personal selling encourages favorable word-of-mouth marketing to additional target markets, raising brand recognition and exposure (Sharma and Iyer 2010).H6: Personal selling has a positive impact on customers' GBA.For each expected factor, we designed statements to measure their aspects and based on a form of 5-point likert scale ranging from 1-Strongly disagree to 5-Strongly agree (21 statements for 6 independent variables and 3 statements for 1 dependent variable) (table 1).

Data collection and analysis
This study was reviewed and approved by the Scientific and Training Council of the National Economics University, Vietnam which has the responsibility of academic ethics approval (Reference Code: CBQT.29.2023).The research was conducted in accordance with the principles embodied in the Declaration of Helsinki and in accordance with local statutory requirements.All participants gave written informed consent to participate in the study.
Research data were collected through a survey.In phase 1, the questionnaire was designed based on group discussions with 10 consumers, market management agencies and businesses with green brands.Then, the research conducted a pilot survey with 12 customers to validate the questionnaire and complete the interview strategy.In phase 2, we developed investigation strategies and plans, determined survey samples, collected information to select samples and conducted official investigations.The formal survey was conducted according to the guidelines of Baruch andHoltom (2008), andHair et al (2013).
The subject of the study was defined as customers in Vietnam.Due to limited resources, we only collected data through surveys in Hanoi city.The following formula was used to estimate the sample size (Hair et al 2013): Of which n is sample size, z is z-score, e is margin of error, and p is standard deviation.Supposed with a 90% confidence level, 50% standard of deviation and a 5% margin of error (z-score as 1.65 was used), the sample to ensure reliability was 580.In fact, we collected 615 questionnaires in Hanoi through face-to-face interviews.
In the survey, respondents were selected from 6 metropolis districts of Hanoi city including Hoan Kiem, Hai Ba Trung, Dong Da, Ba Dinh, Long Bien, and Thanh Xuan.These are districts that represent the economic, social, income and occupational diversity of Hanoi residents.In each district, we made a list of wards and then randomly selected 3 communes to collect data.The average sample size in each district was 102, specifically we conducted 34 surveys/commune (only in Thanh Xuan district, 35 questionnaires for each commune were collected).After selecting the wards, the research team collected a list of residential groups from the local government and randomly drew 3 residential groups in each group.The lists of households in each residential group were collected from the residential group leader.In each residential group, the researcher randomly drew and met 10-14 households for interviews.During the survey, we met with households in the evening to facilitate responding and for the households to have enough people.Absent households were replaced by backup households also randomly drawn from the list provided (table 2).
Before answering the questions, the interviewee was specifically introduced to the objectives of the interview and the purpose of the research.At the same time, they were asked if they agreed and were willing to participate in the interview.All respondents agreed and were willing to participate and ticked into the option of confirm to participate and signed the consent form.
The final questionnaire included 4 main section (1) Introduction of the goal of research and interview, (2) Information about people vehicles of GBA communications (3) Respondents' evaluation about IMC factors impacting GBA, and (4) Demographic characteristics of respondents.The official survey was conducted in October and November 2023 in Hanoi, Vietnam.
After collection, data was cleaned and imported into SPSS 23.0 analysis software.First, we calculated the descriptive statistics, frequencies and crosstabs of the observed variables as well as the correlation of these variables.After that, Cronbach's Alpha technique was employed to test the reliability of observed variables.Then, the study conducted exploratory factor analysis (EFA) to evaluate the convergence of observed variables on separate factors.From there, multiple regressions were carried out to examine the relationship between dependent and independent variables.The study also additionally used One-way ANOVA to test the difference in GBA between groups of respondents with separated social factors such as gender, age and the last purchase.
The equation describing the relationship between GBA and independent variables was shown as follows:  PR 1: I commend the company's public relations efforts in maintaining green brands consistent image and messaging.PR 2: Green brand public relations activities provide informative and attractive product prominence.
PR 3: Green brands release of public relations messages effectively conveys a positive image.Personal selling (PS) PS 1: The salesperson I interacted with demonstrated a deep knowledge of the products/services.PS 2: The salesperson was friendly and approachable during the interaction.PS 3: The salesperson effectively communicated the features and benefits of the products/services.
PS 4: The salesperson provided adequate support and information to help me make a decision.Green brand awareness (GBA) BA 1: I think of the green brand when I buy things BA 2: I can be aware of the characteristics of green products BA 3: I can remember the logos and images of green brands Source: Research results (2023) Of which α was intercept, β i were regression coefficients and e was the impact of unobserved variables in the model.

Socio-economic characteristics of the survey sample
In this study, there was 615 questionnaires distributed and collected.After collecting, 19 observations were removed due to lack of information.Thus, 596 observations were suitable for data analysis.The number of survey participants is mainly between 18-35 years old with 52.92% of surveyors in the age group from 18 to 25 and 20.88% of surveyors in the age group of 26-35 years old.The remaining 18.94% of people are under the age of 18 and 7.26% are in the age group of over 35.The majority of people surveyed had university/college education with 38.94%.In addition, 26.02% of people have just reached the high school level of education and 24.07% of those surveyed have higher level of education.The remaining 10.97% of people have other level of education.
Income groups are relatively equal in the survey sample.Of which the lowest income group (under 10 million VND/month) accounts for 24.96%, the middle income group (from 10 to 20 million VND/month) accounts for 20%, and the high income group (20-30 million VND/month) accounts for 32.92%.The high income group (over 30 millionVND/month) accounts for 22.12% (table 3).

Cronbach's Alpha analysis results
To evaluate the reliability of the scale in research model, the authors conducted Cronbach's Alpha analysis (Hair et al 2013).The results of the first round analysis showed that observed variable AD2 had a Cronbach's Alpha coefficient 'if the variable is removed' (0.845) was higher than the overall Cronbach's Alpha value (0.781).Therefore, this variable was excluded.After removing AD2 and re-running the Cronbach's Alpha test for the second round of which all scales showed reliability (Cronbach's Alpha coefficients >0.6 and total variable correlation coefficients >0.3).Thus, these variables were used for subsequent EFA analysis (table 4).

Exploratory factor analysis results
In the next step, to evaluate the convergence of observed variables into specific factors, we conducted EFA with Factor Extraction as Principal components.The implementation of EFA allowed identifying meaningful factor groups and new factor groups if any.
Results of EFA for the independent variable showed that the KMO coefficient value was 0.777 belonged to range from 0.5 to 1; Bartlet's test gave the value sig.= 0.000 < 0.05 indicating that the factor analysis was reliable and valid (Hair et al 2013).The coefficient of variance extracted for the analysis reached a value of over 50%, and was equal to 71.916, showing that the factors given from the analysis explained 71.916% variation of the survey dataset.The Eigenvalues coefficient was 1.315 > 1, showing high the convergence of 6 given factors in the analysis.Thus, all observed variables were retained in original 6 factors and could be used for regression of impacted factors (table 5).
Regarding dependent variable (GBA), EFA results had coefficient KMO = 0.689 > 0.5 and Sig. of Bartlett's test = 0.000 < 0.05 showing that EFA was valid and reliable for dataset.Eigenvalue = 2.157 > 1 at the first factor with cumulative of eigenvalue = 71.916%> 50% which suggested that there were 1 factor with 3 observed variables explaining for the dependent variable GBA and 71.916% of the data was explained by this factor.

Regression analysis results
The results of the Pearson correlation analysis showed that all the independent variables had a linear relationship with the dependent variable.In which, the variable DM had the highest correlation coefficient with the dependent variable (r = 0.402) and the variable SP had the lowest correlation coefficient with the dependent variable (r = −0.041).The independent variables were correlated with each other in some variables, but the degree of correlation was not significant.With the above results, all the independent variables were eligible to be included in the regression analysis (Hair et al 2013) (table 6).
The model's regression results showed that the value adjusted R 2 = 0.649 suggesting that 64.9% of the variation of GBA was explained by 6 factors in the model.F-test with sig.= 0.000 (< 0.05) indicated that there exists a linear regression model between GBA and influencing factors (table 7).
The regression results also showed that all regression coefficients were significant at the 1% to 5% error level.Thus, there were significant relationships between the dependent variables ICM and GBA.Among them, AD was the variable with the strongest impact on GBA and PS was the variable with the weakest impact.Analysis results proved that all hypotheses were accepted.All VIF coefficients in the regression had values less than 2, so multicollinearity did not occur.The Durbin-Watson coefficient was 1.683, between 1.5 and 2.5, showing that autocorrelation did also not happen (Hair et al 2013).To check the normal distribution assumption of the residuals, the study used the histogram of the residuals.The figure below showed a normal distribution of standardized residuals with bell-shaped.Observing the graph we see, the mean = 1.31E-15 (close to 0) and standard deviation = 0.984 (close to 1).Thus, the assumption of normal distribution of residuals was not violated.In addition, the P-P Plot was also used to identify violations of the normalized residual assumption.In P-P Plot, the dots were centered on the diagonal, so it did not violate the regression assumption about the residual normal distribution (figure 2).Also, the normalized residuals were distributed centered on the zero-coordinate line and not scattered too far, so uneven variance did not occur in the regression model (figure 3).

Impact of socio -economic factors on GBA
The study used Anova test to analyze the difference between the average values of GBA scores according to demographic factors of respondents.Regarding gender, the results showed that men's GBA score was 3.421 while women's was 3.508 and testing sig.was 0.062 (>0.05), thus there was not a significant difference between men and women in their GBA scoring.With age variable, Sig.equal to 0.012 showing the significant difference between age groups in GBA.Tamhane's test with pairwise variance indicated that there was a significant difference between the age group 18-25 compared to the two older age, the 26-35 year old group and the over 35 year old group (Sig.= 0.00 < 0.05) In addition, results of descriptive statistics on the level of GBA by the last purchase had an average rating of 3.442.In which, the criterion 'above 3 months' was the lowest with average score of 3.384; the criteria 'less than 1 months' was ranked the highest with average score of 3.557.ANOVA test showed sig.was 0.095 (>0.05), so last time of purchase did not affect customers' GBA (table 8).

Discussions and implications
This study examined the impacts of IMC on customers' GBA in Vietnam.Using ABC theory to build an empirical test model, the research indicated that there are were 6 factors of IMC impacting customers' GBA including (1) Advertising, (2) Direct Marketing, (3) Internet Marketing, (4) Sales Promotion, (5) Public Relations, and (6) Personal Selling.
The work added to the existing literature on green marketing by confirming that customers' GBA is influenced by psychological factors and customers' personal characteristics.The relationship between psychological factors and GBA has been established in many previous studies using theoretical models ranging from TPB, TAM and ABC.Wilson's (1984) popular biophilia hypothesis holds that humans are innately connected to nature.Green marketing communications with visual cues from nature can trigger an emotional connection that will further influence positive GBA.This is also important for the hierarchy of communication  effect models, in which attention is emphasized as dominant in initiating desired actions.Consistent with the 'image primacy effect,' consumers tend to pay more attention to nonverbal images than to text-based verbal messages.In the GBA context, images of nature in advertising evoke an emotional connection between the advertised brand and nature (Kumar et al 2020, Grubor andMilovanov 2021).
Another important theoretical implication of this study concerns environmental values.As emphasized in the introduction, most previous studies ignore the importance of consumers' environmental values and their important role in IMC affecting GBA.Theoretically, these values could increase consumers' ethical satisfaction through GBA participation.These values are often measured by their commitment to protecting the environment.Accordingly, the results showed consumers' environmental values significantly and positively influence GBA, signaling a sense of being morally responsible for protecting the environment.It is therefore posited here that such feelings of consumer obligation could be enhanced by integrating moral appeal in green marketing communications.
There were also some practical implications from findings of the paper: Firstly, 'Advertising' was the factor that had the strongest impact on GBA (β = 0.262), followed by Internet marketing (β = 0.248) and Direct marketing.(β = 0.164).In fact, advertising plays a crucial role in establishing a brand's identity by communicating its values, personality, and unique selling propositions.Through creative visuals, slogans, and storytelling, advertising helps shape the brand's identity and differentiate it from others and competitors (Brown andZablah 2011, Goh andBalaji 2016).The results showed that the influence of advertising media on GBA is generally significant, with respondents on average rating the influence of media on their GBA as fairly high.Looking at the media alone, social media had the greatest influence on respondents' GBA, followed by the Internet, television, newspapers and radio.These results suggested that social networks were one of the most powerful media and their influence on consumers in Vietnam was huge, especially in the 18-40 age groups.This is consistent with the very popular social media usage trend in Vietnam.Vietnam currently has 65 million Facebook, Tiktok and Instagram users.Interaction via social networks for buying and selling and brand recognition has been also growing rapidly with the increase in internet infrastructure.In addition, Vietnam has a young population with 60% of the population aged 18-40 years old (Mai et al 2023).This promotes the role of digital marketing, especially through social networks and social groups.Chen and Chang (2012), Wang et al (2018), Chu and Chen (2019) also has similar research results in China, Malaysia and Korea, countries with young population structures and developed Internet and social networks.This result provides implications for managers and businesses to continue promoting advertising via social networks to increase green brand recognition in the minds of consumers in Vietnam.It takes a long time to form a brand image, but to become a strong creative industry; they must continue to learn how to build a good brand image in the minds of consumers.
The second type of media in terms of its influence on respondents' opinions about GBA was the Internet.The Internet is a modern advertising medium characterized by consumer interactivity and targeting.What is also notable in the results regarding the influence of the Internet on respondents' GBA is that a statistically significant association exists across respondents' age.The results showed that the younger the respondents, the higher the value they give to the influence of the Internet on their GBA and vice versa.It can be concluded that the Internet is a suitable medium for advertising products, services or events aimed at young people, such as nightclubs, trendy products and the like.This result was consistent with previous studies of (Chong et al 2011, Kinoti 2011, Baumgarth 2014).To gain a competitive advantage over similar industries, the creative industries' environmentally friendly products must be well positioned in the minds of consumers.This can be achieved by further implementing the marketing of environmentally friendly products using innovative means on the Internet.It may take a long time to form a brand image, but to become a strong creative industry; they must continue to learn how to build a good brand image in the minds of consumers.Survey results showed that 'Direct marketing' ranked third in terms of influence on respondents' GBA, and there was no statistically significant difference when it came to their influence on respondents' GBA observed by gender and time of last purchase.However, there was a statistically significant relationship between respondents' age and the effect of direct marketing on their GBA.Younger respondents rated this medium higher and vice versa, suggesting that this medium can be used for products aimed at youth, as is the case with the Internet.These findings were consistent with the results by Indumathi (2018), andChen et al (2020).
Research also indicated that promotions also significantly impacted GBA.Therefore, this study emphasizes the positive contribution of sales promotion to brand awareness.In addition to the benefits gained from promotions, consumers also have the opportunity to discover new features and benefits of products and services being promoted.This situation, in turn, might encourage repeat purchases and active consumer participation, such as the spread of positive word of mouth (Chen andChang 2012, Rambocas andRamsubhag 2018).Therefore, companies should continue to increase consumer awareness of their business activities by promotion.Additionally, the type of promotion can have a different impact on brand perception.Kang and Hur (2012), Joshi and Rahman (2015), Papista and Dimitriadis (2019) emphasized the need to distinguish between two types of promotional measures: monetary measures (e.g.free products, coupons), are associated with utilitarian benefits and help consumers increase the income benefits of purchases and effectively improve your shopping experience; and non-monetary promotions (e.g., contests, free gifts, loyalty programs) tied to hedonic benefits.And by their very nature, they are rewarding and related to experiential emotions, joy, and self-esteem.Studies by Chen and Peng (2018), Hutchins and Rodriguez (2018), showed that brands with high, medium and low awareness achieve different results due to different levels of promotion.Furthermore, Kang and Hur (2012), Lipiäinen and Karjaluoto (2015) indicated that consumers prefer monetary promotions such as discounts for products with low brand awareness, while they prefer non-monetary promotions as bad as giving away free extras for products with high brand awareness.Therefore, this study encourages future researchers to explore the role of sales promotion in building strong customer relationships and achieving competitive advantage through GBA.
Finally, this study had some limitations and could be improved in future studies.First, the study used crosssectional and self-reported information from individuals, which may include bias in social aspirations and may not necessarily reflect actual behavior.Therefore, more research is needed on the factors that influence actual behavior with GBA as the mediating variable.Such an approach will look at the GBA issue more deeply and reveal insights about the impact of GBA on the actual behavior of customers.Second, the study was only conducted with a fairly small sample of residents of urban Hanoi.The picture of results and implications will be more complete if the research sample is replicated in other cities and regions in Vietnam, with different cultural and social characteristics.In addition, this study only analyzed GBA from a general perspective, future studies can specifically localize to certain products, from which the management implications will be clearer and better customized.
3.1.Study modelFrom the established hypotheses, figure 1 presented the conceptual model of this study.The model showed potential IMC factors and their impacts on customers' GBA: In the study, we inherited the methods to measure IMC factors and observed variables from previous literature (Chen and Peng 2018, Rambocas and Ramsubhag 2018, Wang et al 2018, Chu and Chen 2019, Chen et al 2020).

Figure 2 .
Figure 2. Histogram of residual distribution and normal P-P plot of standardized residuals.Source: Research results (2023).

Figure 3 .
Figure 3. Scatter plot to test the assumption of uneven variances.Source: Research results (2023).

Table 1 .
Factors and observed variables in analytical model.

Table 3 .
Characteristics of the sample.

Table 4 .
Summary of scale testing results.

Table 5 .
EFA for independent variables.

Table 8 .
Anova results of GBA mean difference by social factors.